In narration of how Steppenwolf was stopped in Justice League, we can see Green Lantern fighting with Amazonians and other heroes.
So after that is there any hint on what happened to Green Lantern or where the Green Lanterns are?
We just see a single Lantern (although some articles say there may be two, it's only a brief clip) during the fight with Steppenwolf.
The non-human Lantern is killed and his ring flies off (as per the comics) to find a new owner.
Toward the beginning of the movie, we see a flashback sequence, in which, Steppenwolf is seen trying to conquer Earth many years ago. In the sequence, the clans of man, the warriors of Atlantis and the Amazons all band together to take down Steppenwolf and his army. During this battle, we see a brief clip of Yalan Gur, a lesser-known but powerful member of the Green Lantern Corps. Sadly, after a pretty heroic move, Yalan Gur is killed by Steppenwolf and his Lantern ring is seen flying off to an unknown location.
Other than that there is no mention of Green Lanterns or the Lantern Corps.
One trailer even had Justice League's villain Steppenwolf say, "No protectors here. No Lanterns. No Kryptonian. This world will fall like all the others."
(Incidentally, that line never made it into the final cut.)
There is not a single mention of Green Lanterns after the war of all united league(Humans, Amazons, Atlanteans, Gods...) against Steppenwolf's previous attempt to invade Earth.
Also, although Armie Hammer says that he is NOT in the Justice League, there is some evidence that he is probably in the upcoming movies.
No, there's no hint of the GL as the previous answers have mentioned.
However, according to comicbook.com there was a planned post-credits scene which included two well known Green Lanterns confronting Bruce Wayne. But it wasn't included.
Maybe it will appear as a DVD/Blu-ray deleted scene, who knows.