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 (
    2280, 2327, 2328, 2329, 2330, 2394, 2395, 
    2396, 2397, 2398, 2399, 2400, 2401, 
    2402, 2505, 2506, 2507, 2508, 5876, 
    5877, 5878, 5879, 5880, 5926, 5927, 
    5928, 5929, 5930, 5994, 5995, 5996, 
    5997, 5998, 5999, 6000, 6001, 6002, 
    6105, 6106, 6107, 6108, 1653, 2224, 
    1599, 1572, 2603, 6191, 2509, 1626, 
    2281, 2282, 2283, 2284, 2285, 2331, 
    2332, 2333, 2334, 2335, 2403, 2404, 
    2405, 2406, 2407, 2408, 2409, 2410, 
    2411, 2599, 2600, 2601, 2602, 5881, 
    5882, 5883, 5884, 5931, 5932, 5933, 
    5934, 6003, 6004, 6005, 6006, 6007, 
    6008, 6009, 6010, 6011, 6192, 6193, 
    6194, 6195, 2595, 2596, 2597
  ) 
  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 0.00220

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.66"
    },
    "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": 97,
        "rows_produced_per_join": 19,
        "filtered": "20.00",
        "index_condition": "(`gaseus`.`cscart_product_prices`.`product_id` in (2280,2327,2328,2329,2330,2394,2395,2396,2397,2398,2399,2400,2401,2402,2505,2506,2507,2508,5876,5877,5878,5879,5880,5926,5927,5928,5929,5930,5994,5995,5996,5997,5998,5999,6000,6001,6002,6105,6106,6107,6108,1653,2224,1599,1572,2603,6191,2509,1626,2281,2282,2283,2284,2285,2331,2332,2333,2334,2335,2403,2404,2405,2406,2407,2408,2409,2410,2411,2599,2600,2601,2602,5881,5882,5883,5884,5931,5932,5933,5934,6003,6004,6005,6006,6007,6008,6009,6010,6011,6192,6193,6194,6195,2595,2596,2597))",
        "cost_info": {
          "read_cost": "65.72",
          "eval_cost": "1.94",
          "prefix_cost": "67.66",
          "data_read_per_join": "465"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`gaseus`.`cscart_product_prices`.`lower_limit` = 1) and (`gaseus`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}