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 (
    1055, 1056, 1057, 1058, 1050, 1051, 1052, 
    1049, 1067, 1033, 1034, 1037, 1035, 
    1036, 1038, 1032, 1062, 1061, 1060, 
    1063, 1059, 1064, 1066, 1040, 1072, 
    1054, 1053, 1070, 1044, 1039, 1071, 
    1041, 1042, 1065, 1043, 1047, 1048, 
    1069, 1031, 1046, 1045, 1068
  ) 
  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 0.00068

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "181.16"
    },
    "grouping_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "84.00"
      },
      "table": {
        "table_name": "cscart_product_prices",
        "access_type": "ALL",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "rows_examined_per_scan": 465,
        "rows_produced_per_join": 83,
        "filtered": "18.06",
        "cost_info": {
          "read_cost": "80.36",
          "eval_cost": "16.80",
          "prefix_cost": "97.16",
          "data_read_per_join": "1K"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`cscart`.`cscart_product_prices`.`lower_limit` = 1) and (`cscart`.`cscart_product_prices`.`product_id` in (1055,1056,1057,1058,1050,1051,1052,1049,1067,1033,1034,1037,1035,1036,1038,1032,1062,1061,1060,1063,1059,1064,1066,1040,1072,1054,1053,1070,1044,1039,1071,1041,1042,1065,1043,1047,1048,1069,1031,1046,1045,1068)) and (`cscart`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}