Several databases (MS SQL Server, MariaDB, Postgres with appropriate extension) support system versioned temporal tables (added in the SQL2011 standard, though

Several databases (MS SQL Server, MariaDB, Postgres with appropriate extension) support system versioned temporal tables (added in the SQL2011 standard, though I don't know if any DB entirely follows the standard) which I'm pretty sure counts as "queries across time". Maybe they are claiming to be the first with it built-in as a core part of the engine that it is specifically optimised for, but even that might not be true.