[TigerC10]

You can try...

INSERT INTO rank_players (...) ON DUPLICATE KEY UPDATE (...)

OR

REPLACE INTO rank_players (...)

Otherwise you'll just have to do a select query first, and then based on the results of the select query change your insert query.

EDIT:
Just found this...

INSERT INTO Timeline (name, ts)

SELECT @name, @ts

WHERE NOT EXISTS (SELECT 1 FROM Timeline WHERE name=@name AND ts = @ts);

It's worth a try.