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 (
    32849, 32850, 32851, 32852, 32853, 32854, 
    32855, 32856, 32857, 32858, 32859, 
    32860, 32861, 32862, 32863, 32864, 
    32865, 32866, 32867, 32868, 32869, 
    32870, 32871, 32872, 32873, 32874, 
    32875, 32876, 32877, 32878, 32879, 
    32880
  ) 
  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": "132.81"
    },
    "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": 72,
        "rows_produced_per_join": 14,
        "filtered": "19.99",
        "index_condition": "(`portal`.`q_product_prices`.`product_id` in (32849,32850,32851,32852,32853,32854,32855,32856,32857,32858,32859,32860,32861,32862,32863,32864,32865,32866,32867,32868,32869,32870,32871,32872,32873,32874,32875,32876,32877,32878,32879,32880))",
        "cost_info": {
          "read_cost": "129.93",
          "eval_cost": "2.88",
          "prefix_cost": "132.81",
          "data_read_per_join": "345"
        },
        "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)))"
      }
    }
  }
}