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 (
    1914, 1915, 1761, 2203, 1789, 1811, 1791, 
    1889, 1836, 1799, 1845, 1792, 1905, 
    1806, 1837, 2282, 2002, 1940, 2295, 
    2283, 1970, 2387, 2014, 2355, 1996, 
    2286, 2285, 2310, 1997, 1956, 1971, 
    2316, 1955, 2334, 2108, 2360, 2287, 
    2288, 2009, 1950, 2109, 2107, 2221, 
    2023, 2123, 1982, 1944, 2031, 2032, 
    1920, 2033, 2034, 2165, 2223, 2190, 
    1758, 2365, 2067, 2294, 2070, 2069, 
    1835, 1871, 2241, 2351, 2091, 1959, 
    1981, 2137, 2340, 1745, 2209, 2063, 
    2370, 2377, 1916, 2381, 2392, 1838, 
    1766
  ) 
GROUP BY 
  cscart_products_categories.product_id

Query time 0.00110

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "26.24"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "2.15"
      },
      "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": 2,
            "filtered": "4.65",
            "index_condition": "(`cscartdevel`.`cscart_products_categories`.`product_id` in (1914,1915,1761,2203,1789,1811,1791,1889,1836,1799,1845,1792,1905,1806,1837,2282,2002,1940,2295,2283,1970,2387,2014,2355,1996,2286,2285,2310,1997,1956,1971,2316,1955,2334,2108,2360,2287,2288,2009,1950,2109,2107,2221,2023,2123,1982,1944,2031,2032,1920,2033,2034,2165,2223,2190,1758,2365,2067,2294,2070,2069,1835,1871,2241,2351,2091,1959,1981,2137,2340,1745,2209,2063,2370,2377,1916,2381,2392,1838,1766))",
            "cost_info": {
              "read_cost": "11.56",
              "eval_cost": "0.22",
              "prefix_cost": "24.09",
              "data_read_per_join": "34"
            },
            "used_columns": [
              "product_id",
              "category_id",
              "link_type"
            ]
          }
        }
      ]
    }
  }
}