Your car doesn't have regular operating hours. It needs to be ready to go at any time, and it doesn't matter if it's late, on the weekend, or during a holiday. A car is only ready to go when you can actually get into it, so being locked out of your car is obviously a huge problem, and this problem might need to be solved outside of regular operating hours. The solution isn't going to be difficult, but there are a few points to cover before you call for assistance.
A Potentially Dangerous Situation
There are different types of emergencies. In some cases, every second counts, such as if your children or pets are trapped inside the vehicle. In this particular emergency, you should call 911, or consider safely breaking your vehicle's window and worrying about the damage later. When it's not quite such an urgent matter where someone is at immediate risk, call an emergency locksmith.
Calling a Locksmith
Not only will the locksmith quickly be on the scene (which is largely the point of an emergency callout), but they can just as quickly get you back into your car. While doing so, they can also assess your locks, if needed. Perhaps the keys are actually locked inside the vehicle, but the key could just as easily be in your hand and the reason why it's not working is a total mystery. The locksmith can look for signs of tampering (which are often discreet). This can indicate someone has attempted to break into your vehicle, damaging it in the process. Repairs might not be possible at the scene but they must take place as soon as possible.
Verifying Your Identity
Will the locksmith require any proof that the vehicle in question is actually yours? This can differ and is usually a matter of policy. You should be prepared to identify yourself in some way, and the locksmith might ask to see your driver's license before opening your car. Your vehicle registration would also be helpful, although this might be safely locked inside. When requesting an emergency callout, you may wish to ask if they have any identification requirements.
Getting back into your vehicle after being locked out is actually a simple process for a professional locksmith, although you need to recognize the fact that further work will be needed (in the event of an attempted break-in), and that you might need to prove you have the right to gain entry to the car.