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 (
    4974, 5376, 5397, 4995, 5549, 4992, 4991, 
    5346, 6823, 5472, 5387, 5565, 5309, 
    5386, 5568, 5393, 4988, 5468, 5394, 
    5375, 5396, 4961, 5467, 5370, 5566, 
    4989, 5377, 5369, 5567, 5477, 5374, 
    5550, 5388, 5541, 5564, 5544, 5555, 
    5371, 5392, 5466, 5390, 5372, 5473, 
    6773, 5546, 5391, 5389, 5398, 5469, 
    5543, 5470, 5547, 5534, 5471, 5538, 
    5542, 5548, 6245, 6253, 6241, 6207, 
    6220, 6243, 6553, 7516, 11255, 11277, 
    11280, 10412, 7514, 7521, 7515, 7519, 
    7524, 10371, 11222, 10411, 11102, 11112, 
    10999
  ) 
  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 0.00223

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.71"
    },
    "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": 106,
        "rows_produced_per_join": 21,
        "filtered": "19.99",
        "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`product_id` in (4974,5376,5397,4995,5549,4992,4991,5346,6823,5472,5387,5565,5309,5386,5568,5393,4988,5468,5394,5375,5396,4961,5467,5370,5566,4989,5377,5369,5567,5477,5374,5550,5388,5541,5564,5544,5555,5371,5392,5466,5390,5372,5473,6773,5546,5391,5389,5398,5469,5543,5470,5547,5534,5471,5538,5542,5548,6245,6253,6241,6207,6220,6243,6553,7516,11255,11277,11280,10412,7514,7521,7515,7519,7524,10371,11222,10411,11102,11112,10999))",
        "cost_info": {
          "read_cost": "65.59",
          "eval_cost": "2.12",
          "prefix_cost": "67.71",
          "data_read_per_join": "508"
        },
        "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)))"
      }
    }
  }
}