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 (
    29201, 29202, 29203, 29204, 29205, 29206, 
    29207, 29208, 29209, 29210, 29211, 
    29212, 29213, 29214, 29215, 29216, 
    29218, 29219, 29220, 29221, 29222, 
    29223, 29224, 29225, 29226, 29227, 
    29228, 29229, 29230, 29231, 29232, 
    29233
  ) 
  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 0.00213

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 (29201,29202,29203,29204,29205,29206,29207,29208,29209,29210,29211,29212,29213,29214,29215,29216,29218,29219,29220,29221,29222,29223,29224,29225,29226,29227,29228,29229,29230,29231,29232,29233))",
        "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)))"
      }
    }
  }
}