Lindsay Lohan -- Rock Around the Clock

One, two, three o'clock, four o'clock rock ... and if you're partying with Lindsay Lohan at Coachella -- it may go even later.

Lilo and her brother Michael hit up the Flaunt magazine after party Friday following night one of Coachella ... and according to the photog, they split at around 3:30 am.

Not bad, considering the concert ended around 12:30ish.

As we previously reported ... Lindsay made her yearly vow to stay sober at the annual music festival -- known for good music and drugs.