where is a good farming spot for epics and legendarys when my char is around lvl 50-60, a boss etc?
nobody?
any easy and fast to reach farm spots?
Depends if you are looking for chests or enemies? I find the run from pine barrens to tyrant’s hold getting the guaranteed treasure trove is a good pretty quick run depending on if you go after mogara and the bloodbriar and ungoliax or not.
enemies / bosses,i never have luck with the chest drops
I used to farm that wasp hive by the twin falls rift. Seems like it was the thing to do back then, probably still is. Lots of heroes and a boss all close to the riftgate.
Also Cronley’s cave is good. You get 2-3 bosses, guaranteed dynamite, and possibly Cronley’s MI ring too.
All in all, most boss runs should do. Just portal to the closest riftgate before a boss and speed through it, killing heroes and the boss only. Biggest trick is to get a gap closing skill. Either use blitz or shadowstrike if you are the right mastery, or equip a Riftstone to one or more weapons and use chaos strike to skip trash content and just get to the boss heroes faster.
Hope that helps, good luck farming 
Killing wasps is easiest and fastest as long as they are in your level range
There really isn’t a set spot until at least the end of elite. Best bet is to just run the most recent accessible boss or even just continue clearing story quests - the upgrades tend to work themselves out by and large.
If you are having trouble in the 50-60 range perhaps try posting your build in the build discussion form asking for help (upload it into grimtools obviously) frequently the problem is either looking for the wrong items or poorly optimized skill choices, neither of which farming would help with.
i am fooling around with some build ideas and need the items,my current ritualist build is ok
oh,another question ,how can i do the ashes boss again? when i try to enter the boss room its locked
You have to kill the 2 guardians each time. Don’t forget valtraxia and krieg on your way
If you are level 50-60 you should just continue playing through the game. I’d recommend getting to 70 before hitting ultimate and achieving revered with the factions you need augments for but that is build and skill dependent. Ultimate is where your pay off comes. Playing through ultimate should net you some pretty decent gear (nothing compared to crucible if you can clear to wave 150 but still.)
For treasure troves, the Decrepit Cellar in Gloomwald is a good one - it is a rather small dungeon, the trove is easy to find, and the entrance is close to a riftgate.
I like the tyrant hold run. You get to farm a bunch of manticores possibly getting one or multiple eyes. You get to kill a bunch of bosses, grab a guaranteed trove that spawns in the easiest to find places and you get to cap off by killing a boss with a higher chance to drop blueprints. The run takes about 3 to 5 minutes depending.