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 (
    4040, 4041, 4117, 4118, 4119, 4120, 4121, 
    4122, 4123, 4171, 4172, 4173, 4174, 
    4175, 4176, 50, 51, 52, 53, 54, 55, 56, 
    97, 98, 99, 100, 101, 102, 103, 182, 183, 
    184, 185, 186, 187, 188, 189, 190, 191, 
    192, 193, 194, 195, 226, 227, 228, 229, 
    230, 231, 232, 264, 265, 266, 267, 268, 
    269, 270, 318, 319, 320, 321, 322, 323, 
    3961, 3962, 3963, 3964, 3965, 3966, 
    3967, 4006, 4007, 4008, 4009, 4010, 
    4011, 4012, 4066, 4067, 4068, 4069, 
    4070, 4071, 4072, 4073, 4074, 4075, 
    4076, 4077, 4078, 4079, 4110, 4111, 
    4112, 4113, 4114
  ) 
  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 0.00239

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.21"
    },
    "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": 96,
        "rows_produced_per_join": 19,
        "filtered": "19.99",
        "index_condition": "(`test2_gaseus`.`cscart_product_prices`.`product_id` in (4040,4041,4117,4118,4119,4120,4121,4122,4123,4171,4172,4173,4174,4175,4176,50,51,52,53,54,55,56,97,98,99,100,101,102,103,182,183,184,185,186,187,188,189,190,191,192,193,194,195,226,227,228,229,230,231,232,264,265,266,267,268,269,270,318,319,320,321,322,323,3961,3962,3963,3964,3965,3966,3967,4006,4007,4008,4009,4010,4011,4012,4066,4067,4068,4069,4070,4071,4072,4073,4074,4075,4076,4077,4078,4079,4110,4111,4112,4113,4114))",
        "cost_info": {
          "read_cost": "65.29",
          "eval_cost": "1.92",
          "prefix_cost": "67.21",
          "data_read_per_join": "460"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`test2_gaseus`.`cscart_product_prices`.`lower_limit` = 1) and (`test2_gaseus`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}