Hair and anything with transparency, reflexion, refraction, etc. are points of contention in Carrara's renderer. You are not the only one. I am having this problem all the time too.

Your render settings, from what I can see, are barely above the minimal settings. So I don't see what you could do to improve the speed.

Don't expect an answer that would speed-up your render tenfold. The problem is with Carrara's ailing renderer. It is in need of a major overhaul.

You could set the anti-aliasing to 'Good' to gain some speed, but then you will eventually get jagged lines in your render. Also setting the object accuracy to 2 pixels might help, but then your render will look amateurish at best.