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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a744199264663de2563aafb9fc1abfeddf208728239f15b0894d64f4186a488' 
  AND token = '6s6ugXlENTttHKFCfoYijq0A6ZcTXrdmULd9W69b1V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

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