SELECT 
  cscart_ult_product_prices.product_id, 
  MIN(
    IF(
      cscart_ult_product_prices.percentage_discount = 0, 
      cscart_ult_product_prices.price, 
      cscart_ult_product_prices.price - (
        cscart_ult_product_prices.price * cscart_ult_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_ult_product_prices 
WHERE 
  cscart_ult_product_prices.product_id IN (
    4135, 4814, 4819, 4820, 4821, 4818, 4816, 
    4822, 4817, 4815, 4827, 4825, 4831, 
    4830, 4829, 4839, 5061, 5060, 4835, 
    4837, 4836, 5111, 5110, 4841
  ) 
  AND cscart_ult_product_prices.lower_limit = 1 
  AND cscart_ult_product_prices.company_id = 1 
  AND cscart_ult_product_prices.usergroup_id IN (0, 0, 1) 
GROUP BY 
  cscart_ult_product_prices.product_id

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_ult_product_prices.product_id",
      "temporary_table": {
        "table": {
          "table_name": "cscart_ult_product_prices",
          "access_type": "ALL",
          "possible_keys": [
            "usergroup",
            "product_id",
            "company_id",
            "lower_limit",
            "usergroup_id"
          ],
          "rows": 44,
          "filtered": 54.54545593,
          "attached_condition": "cscart_ult_product_prices.lower_limit = 1 and cscart_ult_product_prices.company_id = 1 and cscart_ult_product_prices.product_id in (4135,4814,4819,4820,4821,4818,4816,4822,4817,4815,4827,4825,4831,4830,4829,4839,5061,5060,4835,4837,4836,5111,5110,4841) and cscart_ult_product_prices.usergroup_id in (0,0,1)"
        }
      }
    }
  }
}