Actually, YouTube has an automatic algorithm that identifies songs. The license holders have sued them often enough. The first infraction won't cause your account to be blocked, but they will either take down the video or monetize it and send the money to the license holder (depending on what the license holder has chosen). They'll also send a warning.

HOWEVER! You can just find an artist who gives you permission to use their song! Or one in the public domain, like mine... https://steemit.com/video/@improv/steemit-lip-sync-week-number-1