I can report that the ability to customize BibTeX keys is being currently actively worked on by the team, as we know this is an important missing feature. In the meantime, a possible workaround for small libraries (albeit laborious if you have got a large library) is that you can manually set your own citation keys. Select a reference in your library, click the Edit button to open the Edit Details dialog, select Additional Fields, scroll down to Identifiers, select BibTeX key and you’ll find that you can set the BibTeX citation key to whatever you’d like. If you decide to set this field, make sure it is unique in your library. Click Save and Next to change the next citation key.
