BernhardB, thanks for response!
A very nice module, I've found it very useful! Thanks for advice!
But I needed to make cache not for a part of the template, but whole template. (have some specific )
So I came up with the solution, using this module:
(maybe someone will find it useful too)
So now I can make a cache for any template with any cache_key.
I'm sure it's possible to make a Hook using "before render" for certain templates, so that can make cache and keep the template file clean. (or maybe not )
Anyway don't want to do it, ask me if someone need it