Whole game is based on EU times, raiding, dominion, and such.
If you have a morning job in US you are going to miss most of the fun as because that is when most of the fun stuff happens then.
Except for Sunday, that is when when the Dominion 6v6 happens. (about 12:00PM US time depending where you live.)
Don't get me wrong tho, there are people from US that play this game as well but usually not nearly enough at night to do almost anything.
Keys reset about 6-8AM Thursday morning, and most players start then to burn thru them at that time as well.
Raids start anywhere from 11:00AM-13:00PM our time Monday-Friday.
Raids reset on Sunday.
If you work a night shift you should be fine fitting in xD