Yes drano can help to clear out some clogs in an ac drain line but it won't work for all clogs so sometimes you may have to run a pipe snake down the ac drain line to clear more stubborn clogs in the ac drain line.
I pour drano down my ac drain line and it works for smaller clogs but if something is really lodged in there clogging it then I have to use the small plumbers snake to clear the clog.
After every summer ends I clean my ac drain line out and then once again before summer to make sure it's clean and not clogged up.