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 (
    5750, 7013, 5739, 5727, 4432, 1553, 2574, 
    1, 228, 247, 944, 478, 8, 985, 3754, 525, 
    2478, 1552, 10284, 6151, 1274, 908, 
    1930, 1557, 1554, 1560, 3452, 4009, 
    1556, 2527, 1561, 1134, 5696, 2088, 
    4022, 2490, 9, 2698, 1406, 5721
  ) 
  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 0.00142

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "29.36"
    },
    "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": 43,
        "rows_produced_per_join": 8,
        "filtered": "19.99",
        "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`product_id` in (5750,7013,5739,5727,4432,1553,2574,1,228,247,944,478,8,985,3754,525,2478,1552,10284,6151,1274,908,1930,1557,1554,1560,3452,4009,1556,2527,1561,1134,5696,2088,4022,2490,9,2698,1406,5721))",
        "cost_info": {
          "read_cost": "28.50",
          "eval_cost": "0.86",
          "prefix_cost": "29.36",
          "data_read_per_join": "206"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`lower_limit` = 1) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}