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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cac034363b546ded82a1f6c18a2593a9278b58dbe81bca17acfeeac9c40d1c3e' 
  AND token = 'Julhn6mqsUa0CpyAbmA3lZmULwG2rTBTlkfbvJMN1hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE								Impossible WHERE noticed after reading const tables