Hash key not unique in road_usage

[opatut]

sqlalchemy.exc.PendingRollbackError: This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: (sqlalchemy.dialects.postgresql.asyncpg.IntegrityError) <class 'asyncpg.exceptions.UniqueViolationError'>: duplicate key value violates unique constraint "ix_road_usage_hex_hash"
DETAIL:  Key (hex_hash)=(1e7f60c9a9c92b27d4dcbcb414af2b1f647abfc30799e6d893b9ee46c974cbed) already exists.
[SQL: INSERT INTO road_usage (track_id, hex_hash, way_id, time, direction_reversed) VALUES (%s, %s, %s, %s, %s) RETURNING road_usage.id]
[parameters: (328, '1e7f60c9a9c92b27d4dcbcb414af2b1f647abfc30799e6d893b9ee46c974cbed', 824230969, datetime.datetime(2021, 3, 26, 18, 48, 52), False)]
(Background on this error at: https://sqlalche.me/e/14/gkpj) (Background on this error at: https://sqlalche.me/e/14/7s2a)

hope it's not a hash collision.

Originally posted by @SirTificate in #247 (comment)