SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7873d5c21f0d0f1cb439e7394909de441fca773bed40b93fa8b683b09c2a2ae' 
  AND token = 'keWXmkwnBd6t3APw4fCSNL2nsOQ1z5bdSorjt6DPWN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

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