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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '227ea6862512cd22defae0706f8297afde68de8b691b8605929b2f5035dd7556' 
  AND token = '4ez5402PV3QCxi63rgPbQtiK5LmOTwBvyFbmYwPC5WA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

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