Another Day, Another Song! Let's Go~
Answer Is Near by One OK Rock
This is not an actual anime song. However, people have used it mostly in SAO AMVs. Also expecting a Season 3 for the series. One OK Rock is one of the better J-Rock bands nowadays and even have made a name for themselves in the anime community because of this specific song and people mixing it up with SAO. Just give it a try, it's amazing and will easily become one of your favorite J-Rock bands soon enough.
If you listen carefully, you can hear "Kirito" in the lyrics which is why people associate it with SAO. The lyric is actually "Kiito" but I'm gonna believe is Kirito!
Here's an example of what an AMV with this song looks and sounds like and believe me, there are plenty of these out there. You will see that it mixes up pretty damn well with SAO's style and even feel that the song is actually from the anime.
Is SAO Season 3 coming? Do you think it needs another season?
Close your eyes and listen~