I've got a menu in Expensive without use of it's links. Among the products results in this link: http://dev.infinityfitness.pl/rozklad, however the domain isn't mine.

Can you really override this link using htaccess when user clicks within this food selection the redirect leads him to something similar to this http://infinityfit.dnawrot.nazwa.pl/rozklad?

The .htaccess file will have to reside around the domain you do not have use of, regrettably.

You cannot "intercept" client side links within a expensive application without having accessibility source code.