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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50055ef837146cba11e089fab3cf183b39eeb0821f67bce2e09f0b593f950a5b' 
  AND token = 'nK5xyo4YBPw9/JSdQZJ9IWFvZvBliWuTo1en1oO2dAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

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