In case you have your own slow SQL query, you can optimize it automatically here.
For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:
ALTER TABLE `product` ADD INDEX `product_idx_prod_id` (`prod_id`);
ALTER TABLE `user_prod_sel` ADD INDEX `user_sel_idx_seltype` (`seltype`);
SELECT
product.prod_active
FROM
product
WHERE
product.prod_id IN (
SELECT
user_prod_sel.prod_id
FROM
user_prod_sel
WHERE
user_prod_sel.seltype = 100
)