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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '335558d86a2b3f298af3f36f4dabe6424beeda855a3230f8c35dd384fcc6b22c' 
  AND token = 'xn1fIoU1HhZeECd79KoxZNVhYX1bU6QfifihRJJk0ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

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