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 (
    29195, 29201, 29203, 29211, 29212, 29213, 
    29215, 29216, 29223, 29225, 29227, 
    29230, 29233, 29237, 29239, 29242, 
    29243, 29244, 29251, 29252, 29257, 
    29258, 29260, 29270, 29275, 29284, 
    29286, 29288, 29289, 29290
  ) 
  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 0.00091

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "74.81"
    },
    "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": 32,
        "rows_produced_per_join": 6,
        "filtered": "19.99",
        "index_condition": "(`portal`.`q_product_prices`.`product_id` in (29195,29201,29203,29211,29212,29213,29215,29216,29223,29225,29227,29230,29233,29237,29239,29242,29243,29244,29251,29252,29257,29258,29260,29270,29275,29284,29286,29288,29289,29290))",
        "cost_info": {
          "read_cost": "73.53",
          "eval_cost": "1.28",
          "prefix_cost": "74.81",
          "data_read_per_join": "153"
        },
        "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)))"
      }
    }
  }
}