Thank you Balloni55, that is the perfect answer!
I looked into this a bit more earlier and have discovered the following
What I wanted to do was to create a Pocket Query that is centred in Oslo and to then export those results into Locus. I did this by exporting a GPX file and then imported the file into Locus. Then I tried to sort the data by favourite but it did not work. I think the reason is that the exported GPX does not contain favourite data.
I have previously imported a Bookmark List into Locus by using Geocaching4Locus app. This appears to bring in the favourite data. However, you cannot build a Bookmark List that will search like a Pocket Query.
In summary, the way to do it is:
1. Create Pocket query to search exactly the way you want
2. Export the GPX
3. Import the GPX into Locus, put in suitable folder
4. Look at the Points in the folder, click on Spanner symbol, then ^ symbol and Update caches
5. Click on middle button on bottom row and select Geocaching and Sort by Favourite
Thanks to you Balloni55 for your help!