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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a872ab4984fa398cc2d5dc31a9142aef301a6c5b6e446e32727d91269fce28f0' 
  AND token = 'BlfQtUubYwgzYZy7YKKVslaA59MI5z1QT5fWuCaWuxs=' 
  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