Look at what I've just read on the Internet Encyclopedia of Philosophy: "There
I just wanted to add to Allen's remarks (with which I largely agree).
First, the claim that there are no laws of nature that hold just for (e.g.) the planet Earth may require the qualification "no fundamental laws of nature". After all, if it is a law of nature that like electric charges repel, then it is a law of nature that like electric charges on planet Earth repel. The latter is a derivative law, however. So there could easily be non-fundamental laws that hold just for the planet Earth.
Second, on Lewis's own version of the Best System view, the laws of nature must all be truths. There is no trade-off between "complete and perfect truth" and "greater generality." Of course, a modified version of Lewis's account might be more liberal.
Third, it could be that all fundamental laws of physics have no explanations (that's what makes them fundamental, as you say), and yet there is a reason why all fundamental laws of physics cover all of space-time and (to put it roughly) say the same things about every spatiotemporal region. It could be a meta-law of nature that all fundamental first-order laws of physics cover all of space-time and say the same things about every spatiotemporal region. This meta-law would explain why all first-order fundamental laws of physics have these properties. After all, if all of the first-order fundamental laws of physics are like this, then it seems like this fact would not be a coincidence. There would be a common "cause" for all of the first-order laws' being like this.
Finally, notice that we have moved here from laws of nature to laws of physics. Perhaps there are laws of "special sciences" that are restricted in space or in time.