Is there a way to reset the clock in this game, I ran out of time and I can't continue.

If by "ran out of time" you mean you did not attend to a plot-critical quest in time (e.g., the troll invasion), then it's game over. Your option is to load an earlier save and deal with it before some sidequests, or starting a new game entirely.

If you mean you reached the end of the game and don't have time to finish sidequests, then you'll have to try them on another playthrough.

There are mods on the Pathfinder Kingmaker Nexus that will allow you to play with the game clock, although a straight out reset (if any actually support that) could cause issues.

I finished the main quest but I did not have time to explorer the stolen lands, I guess.....

It helps when you try to be efficient with travelling, like trying to do several things in the same region before going back to the capital. Eventually you can also build mage towers and teleportation circles, which enables instant travel between your claimed villages. And once you have some bags of holding, I always found it a good idea to keep at least 12 rations on the party. Hunting for maybe 12 hours each time you rest is a time thief (and I lost days upon days early on due to that).

Wonder how this will be handled in the next game, though, where there isn't supposed to be a time pressure of the same type. I assume they will implement some type of similar mechanic though, as it was an efficient way to reduce rest spamming, which has plagued so many games of this type (and the way they did it in POE was really annoying).

Ultimately, though, what will take up most time is all the upgrades of advisors and regions. 14 days a pop until you can reduce it in half. Meanwhile, a chapter's main threat may be dealt with in a matter of days, at least once a decent chunk of the map is known so you roughly know where to go.