Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84876da43b808ff8ff6f8de99a65c798359058a9ad36c1016592545d7b66aa0e' 
  AND token = '7CumrYM1DWiSCxnS7YsbghcWRFOGlkbTRiTfLe6WxyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

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