So, it looks like this is not possible.
Let me try to explain again what I am trying to do:
1. define the folder in which to search by typing the name: "foldername",
2. selecting it
3. and then searching for an item in it: folder or file by typing its' name "filename"
And the search in 3. would be limited to the folder selected in 2.
Is something like this coming up in Alfred 3?