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 (
    5922, 6170, 37773, 61, 62, 6162, 6163, 
    6168, 6167, 47164, 6160, 6166, 40552, 
    6161, 40553, 6165, 28158, 41952, 41955, 
    47167, 47668, 41954, 47664, 47168, 
    47665, 49290, 41953, 47667, 16567, 
    41956, 47666, 49287
  ) 
  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 0.00271

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "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": 99.9960556,
          "index_condition": "cscart_product_prices.product_id in (5922,6170,37773,61,62,6162,6163,6168,6167,47164,6160,6166,40552,6161,40553,6165,28158,41952,41955,47167,47668,41954,47664,47168,47665,49290,41953,47667,16567,41956,47666,49287)",
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
        }
      }
    ]
  }
}