select t1.*, t2.*
from modx_site_content t1
left join modx_ms2_products t2 on t2.id = t1.id
where t1.id = 541
SELECT `t1`.*, `t2`.*
FROM modx_site_content `t1`
JOIN modx_ms2_products `t2` ON `t1`.`id` = `t2`.`id`
WHERE `t1`.`id` = 541