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 (
    13407, 13408, 13409, 13410, 13411, 13412, 
    13413, 13414, 13415, 13416, 13417, 
    13418, 13419, 13420, 13421, 13422, 
    13423, 13424, 13425, 13426, 13427, 
    13428, 13429, 13430
  ) 
  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 0.00084

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.06190128,
    "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": 0.04656984,
          "filtered": 49.95571136,
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.product_id in (13407,13408,13409,13410,13411,13412,13413,13414,13415,13416,13417,13418,13419,13420,13421,13422,13423,13424,13425,13426,13427,13428,13429,13430) and cscart_product_prices.usergroup_id in (0,1)"
        }
      }
    ]
  }
}

Result

product_id price
13407 12.00000000
13408 20.00000000
13409 19.00000000
13410 13.00000000
13411 15.00000000
13412 12.00000000
13413 21.00000000
13414 15.00000000
13415 12.00000000
13416 12.00000000
13417 18.00000000
13418 12.00000000
13419 21.00000000
13420 15.00000000
13421 15.00000000
13422 15.00000000
13423 12.00000000
13424 12.00000000
13425 12.00000000
13426 12.00000000
13427 16.00000000
13428 14.00000000
13429 12.00000000
13430 21.00000000