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 (
    5770, 461, 40807, 1742, 5763, 4268, 4267, 
    48845, 5758, 47274, 5775, 40802, 1752, 
    40893, 41616, 5764, 5771, 5760, 5773, 
    1758, 5757, 41226, 5768, 40810, 1744, 
    33721, 4303, 5766, 1743, 1753, 35475, 
    48851
  ) 
  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 0.00672

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 (5770,461,40807,1742,5763,4268,4267,48845,5758,47274,5775,40802,1752,40893,41616,5764,5771,5760,5773,1758,5757,41226,5768,40810,1744,33721,4303,5766,1743,1753,35475,48851)",
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
        }
      }
    ]
  }
}