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 (
    10754, 10755, 10756, 10757, 10758, 10759, 
    10880, 10881, 10882, 10883, 10884, 
    10885, 10886, 10887, 10888, 10889, 
    10890, 10891, 10892, 10893, 10894, 
    10895, 10896, 10897, 10898, 10921, 
    10922, 10923, 10924, 10925, 10926, 
    10927, 10928, 10929, 10930, 10931, 
    10932, 10933, 10934, 10935, 10936, 
    10937, 10938, 10939, 10940, 10941, 
    10942, 10943
  ) 
  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 0.00111

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "33.61"
    },
    "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": 48,
        "rows_produced_per_join": 9,
        "filtered": "20.00",
        "index_condition": "(`gaseus`.`cscart_product_prices`.`product_id` in (10754,10755,10756,10757,10758,10759,10880,10881,10882,10883,10884,10885,10886,10887,10888,10889,10890,10891,10892,10893,10894,10895,10896,10897,10898,10921,10922,10923,10924,10925,10926,10927,10928,10929,10930,10931,10932,10933,10934,10935,10936,10937,10938,10939,10940,10941,10942,10943))",
        "cost_info": {
          "read_cost": "32.65",
          "eval_cost": "0.96",
          "prefix_cost": "33.61",
          "data_read_per_join": "230"
        },
        "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)))"
      }
    }
  }
}

Result

product_id price
10754 0.00000000
10755 0.00000000
10756 0.00000000
10757 0.00000000
10758 0.00000000
10759 0.00000000
10880 0.00000000
10881 0.00000000
10882 0.00000000
10883 0.00000000
10884 0.00000000
10885 0.00000000
10886 0.00000000
10887 0.00000000
10888 0.00000000
10889 0.00000000
10890 0.00000000
10891 0.00000000
10892 0.00000000
10893 0.00000000
10894 0.00000000
10895 0.00000000
10896 0.00000000
10897 0.00000000
10898 0.00000000
10921 0.00000000
10922 0.00000000
10923 0.00000000
10924 0.00000000
10925 0.00000000
10926 0.00000000
10927 0.00000000
10928 0.00000000
10929 0.00000000
10930 0.00000000
10931 0.00000000
10932 0.00000000
10933 0.00000000
10934 0.00000000
10935 0.00000000
10936 0.00000000
10937 0.00000000
10938 0.00000000
10939 0.00000000
10940 0.00000000
10941 0.00000000
10942 0.00000000
10943 0.00000000