SELECT DISTINCT `c`.`product_id`
FROM `product_category` AS `c`
JOIN `product_attribute` AS `a1` ON `a1`.`product_id` = `c`.`product_id`
AND `a1`.`attribute_id` = :attribute1 AND `a1`.`text` = :attrValue1
...
WHERE `c`.`category_id` = :categoryId