Literally "May it be easy" or " Easy to come" are similar meanings but they are not commonly used in English. The phrase "Kolay gelsin" is not implying something internal, it means that by the help of God or if the person is not religious with luck may the work you are doing become easy to do for you and you can accomplish it in a short time by this way. 

When I was learning English, I asked this question many times but unfortunately there isn't. When we try to guess, we say "Take it easy" but it doesn't make same sense. 

There isn't anything quite the same.  If someone has a big project to do, you can say something like "Don't work too hard' or 'Don't knock yourself out' but, like I said, they are not quite the same.

I think "Good Job " or "God bless you "

I think maybe "Take it easy" might be similar, based on the other comment, but I'm not sure what you are trying to convey.