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 (
    8607, 8700, 8725, 8798, 8807, 8271, 8274, 
    8278, 8279, 8285, 8287, 8330, 8333, 
    8374, 8389, 8405, 8430, 8458, 8465, 
    8516, 8518, 8537, 8571, 8582, 8584, 
    8588, 8599, 8726, 8728, 8755, 8756, 
    8803, 8809, 8268, 8331, 8334, 8378, 
    8383, 8436, 8442, 8462, 8539, 8541, 
    8579, 8583, 8606, 8727, 8239, 8270, 
    8286, 8376, 8384, 8401, 8402, 8437, 
    8467, 8468, 8515, 8531, 8533, 8542, 
    8616, 8698, 8707, 8386, 8404, 8449, 
    8522, 8591, 8592, 8598, 8786, 8808
  ) 
  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 0.00159

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "51.11"
    },
    "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": 73,
        "rows_produced_per_join": 14,
        "filtered": "19.99",
        "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_prices`.`product_id` in (8607,8700,8725,8798,8807,8271,8274,8278,8279,8285,8287,8330,8333,8374,8389,8405,8430,8458,8465,8516,8518,8537,8571,8582,8584,8588,8599,8726,8728,8755,8756,8803,8809,8268,8331,8334,8378,8383,8436,8442,8462,8539,8541,8579,8583,8606,8727,8239,8270,8286,8376,8384,8401,8402,8437,8467,8468,8515,8531,8533,8542,8616,8698,8707,8386,8404,8449,8522,8591,8592,8598,8786,8808))",
        "cost_info": {
          "read_cost": "49.65",
          "eval_cost": "1.46",
          "prefix_cost": "51.11",
          "data_read_per_join": "350"
        },
        "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)))"
      }
    }
  }
}