SELECT 
  q_product_prices.product_id, 
  MIN(
    IF(
      q_product_prices.percentage_discount = 0, 
      q_product_prices.price, 
      q_product_prices.price - (
        q_product_prices.price * q_product_prices.percentage_discount
      )/ 100
    )
  ) AS price 
FROM 
  q_product_prices 
WHERE 
  q_product_prices.product_id IN (
    32484, 32485, 32486, 32487, 32488, 32489, 
    32490, 32491, 32492, 32493, 32494, 
    32495, 32496, 32497, 32499, 32500, 
    32501, 32502, 32503, 32504, 32505, 
    32506, 32507, 32508, 32509, 32510, 
    32511, 32512, 32513, 32514, 32515, 
    32516
  ) 
  AND q_product_prices.lower_limit = 1 
  AND q_product_prices.usergroup_id IN (0, 1) 
GROUP BY 
  q_product_prices.product_id

Query time 0.00094

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "86.61"
    },
    "grouping_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "q_product_prices",
        "access_type": "range",
        "possible_keys": [
          "usergroup",
          "product_id",
          "lower_limit",
          "usergroup_id"
        ],
        "key": "product_id",
        "used_key_parts": [
          "product_id"
        ],
        "key_length": "3",
        "rows_examined_per_scan": 39,
        "rows_produced_per_join": 7,
        "filtered": "19.99",
        "index_condition": "(`portal`.`q_product_prices`.`product_id` in (32484,32485,32486,32487,32488,32489,32490,32491,32492,32493,32494,32495,32496,32497,32499,32500,32501,32502,32503,32504,32505,32506,32507,32508,32509,32510,32511,32512,32513,32514,32515,32516))",
        "cost_info": {
          "read_cost": "85.05",
          "eval_cost": "1.56",
          "prefix_cost": "86.61",
          "data_read_per_join": "187"
        },
        "used_columns": [
          "product_id",
          "price",
          "percentage_discount",
          "lower_limit",
          "usergroup_id"
        ],
        "attached_condition": "((`portal`.`q_product_prices`.`lower_limit` = 1) and (`portal`.`q_product_prices`.`usergroup_id` in (0,1)))"
      }
    }
  }
}