For Find and most other things, you could do this using a sub-folder clause in the filter. That prevents the contents of certain folders even being considered.
Unfortunately, that won't work with sync. Sync will always consider everything below the starting point. While you can still filter things by path/location, the folders will still be read before filtering, so it only changes the results rather than how long it takes to generate the results.
(More detail here: How to filter items by location or sub-folder )
If you don't need to see and be able to change what will be synced before anything is done, and just want to copy new/modified files from the source to the destination, you can use the Copy Update All command with a copy filter, and that filter can use sub-folder clauses to avoid looking inside certain folders. Ask if that would be useful and you need more detail.