You did not created the index I recommended before:
CREATE INDEX ON granule_file(granule_uuid);
Try creating this index and show us the new generated plan with `EXPLAIN (ANALYZE, VERBOSE, BUFFERS)` (you can paste it at depesz tool).
PS: As said in the other thread, a primary key on (granule_uuid, file_id) would make more sense, but you need to get rid of null values on these rows before creating the PK.
