SELECT 
  cscart_products_categories.product_id, 
  GROUP_CONCAT(
    IF(
      cscart_products_categories.link_type = "M", 
      CONCAT(
        cscart_products_categories.category_id, 
        "M"
      ), 
      cscart_products_categories.category_id
    )
  ) AS category_ids 
FROM 
  cscart_products_categories 
  INNER JOIN cscart_categories ON cscart_categories.category_id = cscart_products_categories.category_id 
  AND cscart_categories.storefront_id IN (0, 1) 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
WHERE 
  cscart_products_categories.product_id IN (
    1987, 
    2110, 
    2111, 
    2112, 
    1900, 
    1813, 
    1820, 
    2366, 
    1897, 
    1750, 
    1924, 
    2227, 
    2204, 
    2010, 
    2309, 
    2060, 
    2122, 
    2274, 
    2061, 
    1918, 
    1913, 
    1958, 
    2290, 
    1751, 
    1957, 
    2202, 
    1814, 
    2331, 
    1748, 
    2005, 
    2214, 
    2342, 
    2215, 
    2211, 
    2225, 
    2212, 
    2213, 
    2226, 
    2151, 
    1882, 
    1815, 
    1853, 
    1759, 
    2001, 
    2276, 
    2231, 
    2281, 
    2379, 
    2388, 
    2115, 
    1929, 
    2373, 
    2372, 
    2374, 
    1760, 
    1807, 
    1847, 
    2363, 
    1816, 
    2146, 
    2201, 
    2386, 
    2359, 
    2279, 
    1843, 
    1859, 
    1794, 
    1793, 
    1817, 
    1795, 
    2278, 
    1818, 
    1784, 
    1819, 
    1849, 
    2338, 
    2383, 
    2337, 
    2336, 
    2389, 
    1802, 
    1801, 
    1880, 
    1767, 
    2346, 
    2301, 
    2081, 
    1947, 
    2157, 
    2207, 
    2142, 
    2121, 
    2375, 
    2088, 
    2089, 
    2090, 
    2087, 
    2158, 
    1787, 
    2105, 
    2133, 
    2125, 
    2092, 
    2093, 
    2046, 
    2045, 
    2044, 
    2047, 
    2049, 
    2048, 
    1995, 
    1943, 
    2120, 
    2094, 
    2385, 
    1989, 
    2314, 
    1951, 
    2096, 
    1988, 
    2098, 
    2097, 
    2099, 
    2199, 
    2200, 
    1948, 
    2095, 
    2100, 
    2124, 
    2101, 
    2134, 
    2198, 
    2291, 
    2103, 
    2307, 
    2166, 
    2208, 
    2102, 
    2104, 
    2345, 
    2143, 
    2119, 
    2144, 
    2362, 
    2233, 
    2350, 
    2232, 
    2244, 
    2051, 
    1855, 
    2367, 
    1808, 
    1891, 
    1892, 
    2368, 
    2393, 
    1952, 
    1939, 
    1930, 
    1764
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00116

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "28.52"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "4.43"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "cscart_categories",
            "access_type": "ALL",
            "possible_keys": [
              "PRIMARY",
              "c_status",
              "p_category_id"
            ],
            "rows_examined_per_scan": 68,
            "rows_produced_per_join": 2,
            "filtered": "4.00",
            "cost_info": {
              "read_cost": "7.63",
              "eval_cost": "0.27",
              "prefix_cost": "7.91",
              "data_read_per_join": "9K"
            },
            "used_columns": [
              "category_id",
              "storefront_id",
              "usergroup_ids",
              "status"
            ],
            "attached_condition": "((`cscartdevel`.`cscart_categories`.`storefront_id` in (0,1)) and ((`cscartdevel`.`cscart_categories`.`usergroup_ids` = '') or (0 <> find_in_set(0,`cscartdevel`.`cscart_categories`.`usergroup_ids`)) or (0 <> find_in_set(1,`cscartdevel`.`cscart_categories`.`usergroup_ids`))) and (`cscartdevel`.`cscart_categories`.`status` in ('A','H')))"
          }
        },
        {
          "table": {
            "table_name": "cscart_products_categories",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY",
              "pt"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "category_id"
            ],
            "key_length": "3",
            "ref": [
              "cscartdevel.cscart_categories.category_id"
            ],
            "rows_examined_per_scan": 17,
            "rows_produced_per_join": 4,
            "filtered": "9.59",
            "index_condition": "(`cscartdevel`.`cscart_products_categories`.`product_id` in (1987,2110,2111,2112,1900,1813,1820,2366,1897,1750,1924,2227,2204,2010,2309,2060,2122,2274,2061,1918,1913,1958,2290,1751,1957,2202,1814,2331,1748,2005,2214,2342,2215,2211,2225,2212,2213,2226,2151,1882,1815,1853,1759,2001,2276,2231,2281,2379,2388,2115,1929,2373,2372,2374,1760,1807,1847,2363,1816,2146,2201,2386,2359,2279,1843,1859,1794,1793,1817,1795,2278,1818,1784,1819,1849,2338,2383,2337,2336,2389,1802,1801,1880,1767,2346,2301,2081,1947,2157,2207,2142,2121,2375,2088,2089,2090,2087,2158,1787,2105,2133,2125,2092,2093,2046,2045,2044,2047,2049,2048,1995,1943,2120,2094,2385,1989,2314,1951,2096,1988,2098,2097,2099,2199,2200,1948,2095,2100,2124,2101,2134,2198,2291,2103,2307,2166,2208,2102,2104,2345,2143,2119,2144,2362,2233,2350,2232,2244,2051,1855,2367,1808,1891,1892,2368,2393,1952,1939,1930,1764))",
            "cost_info": {
              "read_cost": "11.56",
              "eval_cost": "0.44",
              "prefix_cost": "24.09",
              "data_read_per_join": "70"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}