Not just a song that can be found in the archives, but one that almost everyone can hum, even today.
(Somebody asked what was meant by "today's...." Throw whatever you want out, somebody tossed out "Love me tender" as being a tune from in the 1860s.)
While not what one would think of when they think of songs that survive hundreds of years from now, the only song I can think of that's not a folk song that's both archived and hummable (and actually has a tune, so that excludes pop songs)...... is the Pokémon theme song. Go up to anyone and say in tune that you wanna be the very best and someone's gonna ask "like no one ever was".