The SQL:2011 syntax puts the temporal filters directly after base table reference (and before the table alias) [0]
i.e. it would be `SELECT * FROM orders FOR SYSTEM_TIME AS OF "@seq:1000" WHERE customer_id="cust1"` rather than `SELECT * FROM orders WHERE customer_id="cust1" AS OF "@seq:1000"` (the latter being an example from the DriftDB readme)
[0] https://docs.xtdb.com/reference/main/sql/queries.html#_tempo...