SELECT 
  cscart_ult_product_prices.product_id, 
  MIN(
    IF(
      cscart_ult_product_prices.percentage_discount = 0, 
      cscart_ult_product_prices.price, 
      cscart_ult_product_prices.price - (
        cscart_ult_product_prices.price * cscart_ult_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_ult_product_prices 
WHERE 
  cscart_ult_product_prices.product_id IN (
    4, 
    1, 
    5, 
    7, 
    8, 
    9, 
    10, 
    11, 
    12, 
    13, 
    14, 
    15, 
    16, 
    17, 
    18, 
    19, 
    20, 
    21, 
    22, 
    23, 
    24, 
    25, 
    26, 
    27, 
    28, 
    29, 
    30, 
    31, 
    32, 
    33, 
    34, 
    35, 
    36, 
    37, 
    38, 
    39, 
    40, 
    41, 
    42, 
    43, 
    44, 
    45, 
    46, 
    47, 
    48, 
    49, 
    50, 
    51, 
    52, 
    53, 
    54, 
    55, 
    56, 
    57, 
    58, 
    59, 
    60, 
    62, 
    63, 
    64, 
    65, 
    67, 
    68, 
    69, 
    70, 
    71, 
    72, 
    73, 
    74, 
    75, 
    76, 
    78, 
    79, 
    80, 
    81, 
    82, 
    83, 
    84, 
    85, 
    86, 
    87, 
    88, 
    89, 
    90, 
    91, 
    92, 
    93, 
    94, 
    95, 
    96, 
    97, 
    100, 
    101, 
    102, 
    103, 
    104, 
    105, 
    106, 
    107, 
    108, 
    109, 
    110, 
    111, 
    112, 
    113, 
    114, 
    115, 
    116, 
    117, 
    118, 
    119, 
    120, 
    121, 
    122, 
    123, 
    124, 
    125, 
    126, 
    127, 
    128, 
    129, 
    130, 
    131, 
    132, 
    133, 
    134, 
    135, 
    136
  ) 
  AND cscart_ult_product_prices.lower_limit = 1 
  AND cscart_ult_product_prices.company_id = 1 
  AND cscart_ult_product_prices.usergroup_id IN (0, 0, 1) 
GROUP BY 
  cscart_ult_product_prices.product_id

Query time 0.00123

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_ult_product_prices.product_id",
      "temporary_table": {
        "table": {
          "table_name": "cscart_ult_product_prices",
          "access_type": "ALL",
          "possible_keys": [
            "usergroup",
            "product_id",
            "company_id",
            "lower_limit",
            "usergroup_id"
          ],
          "rows": 4,
          "filtered": 100,
          "attached_condition": "cscart_ult_product_prices.lower_limit = 1 and cscart_ult_product_prices.company_id = 1 and cscart_ult_product_prices.product_id in (4,1,5,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,62,63,64,65,67,68,69,70,71,72,73,74,75,76,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136) and cscart_ult_product_prices.usergroup_id in (0,0,1)"
        }
      }
    }
  }
}

Result

product_id price
7 55.000000
11 30.000000
12 30.000000
15 150.000000