SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c58a19b3fc4b92b4489a5f144a38acaf80148045d8e2c1af61fba9df2a0321c4' 
  AND token = '/qaDsGTCJX8tEtyl7+SIYaFyrJ1YpkNp19Wi51uB18g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

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