It's like it's 1993 all over again ... because Ke$ha hit the streets of Hollywood yesterday wearing a fresh pair of L.A. Lights ... the kicks that flash in the heel when you walk.

Ke$ha was braggin' about her new purchase on Melrose Ave. ... telling TMZ, "They light up ... my sh*t lights up!"

L.A. Gear has brought back the light up shoes recently ... and already locked down big name endorsers like LMFAO.

So, we gotta ask ...