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 (
    51567, 51565, 51564, 139, 129, 51566, 
    51301, 51, 50, 51497, 51498, 53, 22713, 
    21, 22714, 22712, 46, 22715, 22716, 
    51496, 21567, 91, 50989, 47, 105, 48, 
    49, 92, 137, 88, 126, 31, 51358, 115, 
    37, 11, 140, 41, 30, 90, 38, 124, 81, 56, 
    135, 82, 116, 117, 125, 106, 39, 193, 
    65, 40, 22710, 22711, 17, 57, 122, 58, 
    5, 22, 18, 27
  ) 
  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 0.00100

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "56.06"
    },
    "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": 89,
        "rows_produced_per_join": 17,
        "filtered": "19.96",
        "index_condition": "(`test_uchur_k`.`cscart_product_prices`.`product_id` in (51567,51565,51564,139,129,51566,51301,51,50,51497,51498,53,22713,21,22714,22712,46,22715,22716,51496,21567,91,50989,47,105,48,49,92,137,88,126,31,51358,115,37,11,140,41,30,90,38,124,81,56,135,82,116,117,125,106,39,193,65,40,22710,22711,17,57,122,58,5,22,18,27))",
        "cost_info": {
          "read_cost": "54.28",
          "eval_cost": "1.78",
          "prefix_cost": "56.06",
          "data_read_per_join": "426"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`test_uchur_k`.`cscart_product_prices`.`lower_limit` = 1) and (`test_uchur_k`.`cscart_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}