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 (
    13016, 13017, 13018, 13019, 13020, 13021, 
    13022, 13023, 13024, 13025, 13026, 
    13027, 13028, 13029, 13030, 10688, 
    10727, 10728, 10729, 10730, 10731, 
    10732, 10733, 10313, 10314, 10315, 
    10316, 10317, 10318, 10319, 10320, 
    10321
  ) 
  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 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_prices",
      "access_type": "range",
      "possible_keys": ["usergroup", "product_id", "lower_limit", "usergroup_id"],
      "key": "product_id",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 32,
      "filtered": 99.23484039,
      "index_condition": "cscart_product_prices.product_id in (13016,13017,13018,13019,13020,13021,13022,13023,13024,13025,13026,13027,13028,13029,13030,10688,10727,10728,10729,10730,10731,10732,10733,10313,10314,10315,10316,10317,10318,10319,10320,10321)",
      "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
    }
  }
}

Result

product_id price
10313 2930.59000000
10314 2930.59000000
10315 2930.59000000
10316 2930.59000000
10317 2930.59000000
10318 2930.59000000
10319 2930.59000000
10320 2930.59000000
10321 2930.59000000
10688 3242.59000000
10727 3242.59000000
10728 3242.59000000
10729 3242.59000000
10730 3242.59000000
10731 3242.59000000
10732 3242.59000000
10733 3242.59000000
13016 1927.73000000
13017 1927.73000000
13018 1927.73000000
13019 1927.73000000
13020 1927.73000000
13021 1927.73000000
13022 1927.73000000
13023 1927.73000000
13024 1927.73000000
13025 1927.73000000
13026 1927.73000000
13027 1927.73000000
13028 1927.73000000
13029 1927.73000000
13030 1927.73000000