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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87e3613001700ed807a65ad653ace198627d9e919898eaa33dff907d383b25bf' 
  AND token = '5AYIaqOJvQicBqki7NANARhPqnmnm5nG71FIW1l8tGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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