SELECT 
  cscart_ult_product_prices.product_id, 
  MIN(
    IF(
      cscart_ult_product_prices.percentage_discount = 0, 
      cscart_ult_product_prices.price, 
      cscart_ult_product_prices.price - (
        cscart_ult_product_prices.price * cscart_ult_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  cscart_ult_product_prices 
WHERE 
  cscart_ult_product_prices.product_id IN (
    174, 175, 176, 177, 178, 179, 180, 181, 
    182, 183, 184, 185, 186, 187, 188, 189, 
    190, 191, 1, 5, 7, 8, 9, 10, 11, 12, 13, 
    14, 15, 16, 17, 18
  ) 
  AND cscart_ult_product_prices.lower_limit = 1 
  AND cscart_ult_product_prices.company_id = 1 
  AND cscart_ult_product_prices.usergroup_id IN (0, 0, 1) 
GROUP BY 
  cscart_ult_product_prices.product_id

Query time 0.00081

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "cscart_ult_product_prices.product_id",
      "temporary_table": {
        "nested_loop": [
          {
            "table": {
              "table_name": "cscart_ult_product_prices",
              "access_type": "ALL",
              "possible_keys": [
                "usergroup",
                "product_id",
                "company_id",
                "lower_limit",
                "usergroup_id"
              ],
              "rows": 4,
              "filtered": 100,
              "attached_condition": "cscart_ult_product_prices.lower_limit = 1 and cscart_ult_product_prices.company_id = 1 and cscart_ult_product_prices.product_id in (174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,1,5,7,8,9,10,11,12,13,14,15,16,17,18) and cscart_ult_product_prices.usergroup_id in (0,0,1)"
            }
          }
        ]
      }
    }
  }
}