How to perform a Boolean AND search with TNTSearch?

By default searching `cats dogs` with TNTSearch shows all results that contain either `cats` **OR** `dogs`.

However, I would like to get only the results that contain both search terms provided.

What I tried:

- `cats AND dogs`
- `cats & dogs`
- `(cats dogs)`
- `+cats +dogs`

None of the queries above does a boolean AND search. 

So what is the correct query in TNTSearch?