My iphone5 charger is broken and i got new one but not the apple one?

So the charger is travel charger and it says charge quickly, constant voltage supply, over volt/over current protection, thermal shutdown protection.( btw its from AFIS korea) My phone really charge faster but i keep getting this message when charging "this cable or accessory is not certified and may not work reliably"
1st is it ok to use this charger? And if its fine then can it be harmful to use travel charger everyday?

If it is charing your phone faster than a regular apple charger did, then it may harm your battery. Think of it like putting water in a paper cup. If you do it from the tap, no problem, do it with a fire hose, and the cup will break. Same basic concept.

You should buy a branded apple charger, local charger can destroy your phone battery or other pats as well.

Like artemisc said AND any charger that not from apple will give you that message