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 (
    452645, 442668, 451860, 438623, 447040, 
    419169, 420289, 433472, 450998, 425857, 
    410176, 457277, 406336, 455410, 458998, 
    417702, 434266, 402632, 403587, 450242, 
    427198, 448492, 425648, 452408
  ) 
  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 0.00165

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.099614043,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_prices",
          "access_type": "range",
          "possible_keys": [
            "usergroup",
            "product_id",
            "lower_limit",
            "usergroup_id"
          ],
          "key": "usergroup",
          "key_length": "9",
          "used_key_parts": ["product_id", "usergroup_id", "lower_limit"],
          "loops": 1,
          "rows": 48,
          "cost": 0.08425304,
          "filtered": 50,
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.product_id in (452645,442668,451860,438623,447040,419169,420289,433472,450998,425857,410176,457277,406336,455410,458998,417702,434266,402632,403587,450242,427198,448492,425648,452408) and cscart_product_prices.usergroup_id in (0,1)"
        }
      }
    ]
  }
}