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 (
    23490, 23487, 23488, 23931, 23492, 23570, 
    23572, 23569, 23499, 23493, 23498, 
    23496, 23495, 23494, 23497, 23428, 
    23467, 23436, 23429, 23489, 23486, 
    23571, 23564
  ) 
  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 0.01170

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_product_prices.product_id",
      "temporary_table": {
        "nested_loop": [
          {
            "table": {
              "table_name": "cscart_product_prices",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "lower_limit",
              "key_length": "3",
              "used_key_parts": ["lower_limit"],
              "ref": ["const"],
              "rows": 11706,
              "filtered": 13.55599213,
              "attached_condition": "cscart_product_prices.lower_limit <=> 1 and cscart_product_prices.product_id in (23490,23487,23488,23931,23492,23570,23572,23569,23499,23493,23498,23496,23495,23494,23497,23428,23467,23436,23429,23489,23486,23571,23564) and cscart_product_prices.usergroup_id in (0,1)"
            }
          }
        ]
      }
    }
  }
}