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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd231940a27a1acbc526f4349e65f31ca6ad59f5ef9589483dd3479d9cb266f26' 
  AND token = 'KZWzsWcAJ5F7Z4YnjtEXbjoLxAY1Lgi81sgXq7Tisrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

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