The time has come ... Nike is FINALLY selling Marty McFly's futuristic high-tops from "Back to the Future II" ... 4 years before they're supposed to exist.

Here's the catch -- Nike is only releasing 1,500 pairs of the Nike Air Mag ... a shoe that Marty rocked in the year 2015 in the movie.

Nike has announced that all of the pairs will be auctioned on eBay ... with all of the proceeds going to the Michael J. Fox Foundation ... which helps fund research on Parkinson's Disease.

According to NiceKicks.com, the shoe contains an LED panel -- just like in the movie -- and is fully rechargeable ... with each charge fueling around 5 hours of awesomeness.

The shoes are great and all ... but seriously, WHERE THE HELL IS THE HOVERBOARD ALREADY?!