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 (
    451077, 403015, 438963, 450825, 401687, 
    443424, 427907, 457801, 454192, 427353, 
    414432, 436128, 421748, 421122, 417392, 
    431455, 406944, 412740, 424119, 412948, 
    446814, 438098, 417337, 414479, 403309, 
    408867, 432076, 429951, 443506, 447548, 
    411429, 410643, 457524, 312409, 312424, 
    312425, 414573, 443819, 451444, 413123, 
    402148, 438958, 422426, 446892, 423821, 
    449843, 410922, 450729
  ) 
  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 0.00237

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.198543966,
    "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": 96,
          "cost": 0.16771496,
          "filtered": 49.99988556,
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.product_id in (451077,403015,438963,450825,401687,443424,427907,457801,454192,427353,414432,436128,421748,421122,417392,431455,406944,412740,424119,412948,446814,438098,417337,414479,403309,408867,432076,429951,443506,447548,411429,410643,457524,312409,312424,312425,414573,443819,451444,413123,402148,438958,422426,446892,423821,449843,410922,450729) and cscart_product_prices.usergroup_id in (0,1)"
        }
      }
    ]
  }
}