Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4a3fb37a03a243663296bf50f8c5c9fc0af3c844cd99fe332837883ce06f74a' 
  AND token = 'jp3LdYewTuDgugWGdOdxYcRSArd3b5sH1HGmCmHJZgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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