Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '947cb2cf3ebca5aaac958270bb49c1ec30b59247e0f27a9751d4aa2e2cd5a8a3' 
  AND token = '2xfn97gErOk3oXcgRARj13yxd2NFo0adibKDC4bOo1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

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