If past and future are actual 'places' that existed somewhere, then this is no more an universe we live in but a multiverse where parallel realms of existence allow humans to travel, visit and return home everyday.
But in the absence of such physical realms of past and future, mind projects a certain future totally based on its past experiences, and its own projection appears like a time travel to the mind.
Same goes for 'going' into past, while mind only retrieves past from its memory from where it is, the moment in the present. Technically speaking nothing in the created universe can take even one step ahead or behind to indulge in a time travel.
Even 'God' cant be traveling in and out of past and future since God (universal consciousness) is supposedly transcending time and not criss-crossing time. Where pervasive consciousness is, there is no place for time of any kind.