there are web sites for finding warrants and your local municipal court. your local police station also should have warrants on file there and you can also call your local sheriff department
The easiest way to find Missouri warrants that have been issued is to get someone to call the county courthouse in Missouri where you think that the warrant was issued from a cell phone and ask. You can also call your local sheriffs office and they can check the national system for you.
If they are traffic warrents you can go the motor vehicle department and they can check the computers. Or, you can call the law enforcement agency directly to check with them.