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 (
    22172, 2157, 38152, 47085, 38146, 38145, 
    3601, 286, 26467, 47148, 4389, 2163, 
    15613, 4393, 1850, 2626, 4392, 38150, 
    4394, 38141, 20830, 38148, 18274, 2159, 
    2162, 732, 38147, 1851, 2148, 1840, 
    1852, 2625
  ) 
  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 0.00202

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "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": 99.9960556,
          "index_condition": "cscart_product_prices.product_id in (22172,2157,38152,47085,38146,38145,3601,286,26467,47148,4389,2163,15613,4393,1850,2626,4392,38150,4394,38141,20830,38148,18274,2159,2162,732,38147,1851,2148,1840,1852,2625)",
          "attached_condition": "cscart_product_prices.lower_limit = 1 and cscart_product_prices.usergroup_id in (0,1)"
        }
      }
    ]
  }
}