When you publish a Level, it will go into a Testing stage (Good or Bad) and it will not be visible on Search until it comes out of that phase. This was done to ensure a fair testing phase without other players being able to search for specific levels to downvote them. We believe this gives a better chance for levels to Succeed!
The normal wait time for players to start testing the newly published levels can vary from 48 to 72 hours.
The number might increase if there are a lot of levels created and very few players testing them. The number gets lower if there are a lot of players testing and very few new levels created.
You can help the queue by playing Good or Bad levels yourself from time to time.