Maybe 30 minutes... if that? You can actually go to the Osceola County Courthouse website and print off their application and have it already filled out. If you do a search for it you will find it. Once you take it up there and have it filled out-- they just make you swear that all the information is valid and then you sign... they give you a copy, you pay, and you head back out-- not much time at all....
I think we spent the majority of the time downstairs waiting in line to go through the medal detectors.
Hope this helps!
Here is the link for the liscense
http://www.osceolaclerk.com/marriage__license__information2.htm
Scroll to the bottom and click for the marriage license form