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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad8753de45937cd85f43e392ba24d27c2a752c46de7fc95af607b83573afd10' 
  AND token = 'UKzgwxxUa7y6LJ8c4rpJUYn5AhPSVBp8YKCMzu87dC4=' 
  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