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 (
    10437, 10438, 10439, 10440, 10441, 10442, 
    10443, 10444, 10522, 9945, 10601, 9727, 
    9728, 9729, 9730, 9731, 9732, 9733, 
    10181, 9734, 9735, 9724, 9803, 9805, 
    9797, 9800, 9799, 9798, 9801, 9802, 
    9806, 9804
  ) 
  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 0.00056

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_prices",
      "access_type": "range",
      "possible_keys": ["usergroup", "product_id", "lower_limit", "usergroup_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 32,
      "filtered": 99.23484039,
      "index_condition": "cscart_product_prices.product_id in (10437,10438,10439,10440,10441,10442,10443,10444,10522,9945,10601,9727,9728,9729,9730,9731,9732,9733,10181,9734,9735,9724,9803,9805,9797,9800,9799,9798,9801,9802,9806,9804)",
      "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
    }
  }
}

Result

product_id price
9724 1482.01000000
9727 1482.01000000
9728 1482.01000000
9729 1482.01000000
9730 1482.01000000
9731 1482.01000000
9732 1482.01000000
9733 1482.01000000
9734 1482.01000000
9735 1482.01000000
9797 1292.58000000
9798 1292.58000000
9799 1292.58000000
9800 1292.58000000
9801 1292.58000000
9802 1292.58000000
9803 1292.58000000
9804 1292.58000000
9805 1292.58000000
9806 1292.58000000
9945 1482.01000000
10181 1482.01000000
10437 1671.44000000
10438 1671.44000000
10439 1671.44000000
10440 1671.44000000
10441 1671.44000000
10442 1671.44000000
10443 1671.44000000
10444 1671.44000000
10522 1671.44000000
10601 1482.01000000