SELECT 
  cscart_product_prices.product_id, 
  MIN(
    IF(
      cscart_product_prices.percentage_discount = 0, 
      cscart_product_prices.price, 
      cscart_product_prices.price - (
        cscart_product_prices.price * cscart_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_product_prices 
WHERE 
  cscart_product_prices.product_id IN (
    2187, 2260, 1861, 1747, 1780, 1797, 1823, 
    1782, 1798, 1772, 1755, 2028, 2118, 
    2116, 2117, 1966, 1967, 1965, 2026, 
    2027, 2131, 1938, 2025, 2062, 2369, 
    1856, 2205, 1846, 1885, 1873, 1824, 
    1869, 2004, 2140, 2139, 2141, 2150, 
    1935, 2003, 2007, 2076, 1867, 2029, 
    2361, 1825, 1826, 2390, 2391, 2270, 
    2272, 2273, 2308, 2378, 2220, 2022, 
    2015, 1980, 1976, 1927, 2058, 1975, 
    1964, 2136, 1749, 1973, 2339, 1974, 
    2354, 1972, 2352, 2030, 2269, 2289, 
    2167, 2128, 1968, 1969, 2192, 2297, 
    2037
  ) 
  AND cscart_product_prices.lower_limit = 1 
  AND cscart_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  cscart_product_prices.product_id

Query time 0.00115

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "60.51"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "product_id",
        "used_key_parts": [
          "product_id"
        ],
        "key_length": "3",
        "rows_examined_per_scan": 90,
        "rows_produced_per_join": 17,
        "filtered": "19.97",
        "index_condition": "(`cscartdevel`.`cscart_product_prices`.`product_id` in (2187,2260,1861,1747,1780,1797,1823,1782,1798,1772,1755,2028,2118,2116,2117,1966,1967,1965,2026,2027,2131,1938,2025,2062,2369,1856,2205,1846,1885,1873,1824,1869,2004,2140,2139,2141,2150,1935,2003,2007,2076,1867,2029,2361,1825,1826,2390,2391,2270,2272,2273,2308,2378,2220,2022,2015,1980,1976,1927,2058,1975,1964,2136,1749,1973,2339,1974,2354,1972,2352,2030,2269,2289,2167,2128,1968,1969,2192,2297,2037))",
        "cost_info": {
          "read_cost": "58.71",
          "eval_cost": "1.80",
          "prefix_cost": "60.51",
          "data_read_per_join": "431"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`cscartdevel`.`cscart_product_prices`.`lower_limit` = 1) and (`cscartdevel`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}