SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8e12807d5205982ddefb2ce68f613db11da75d8dda61cdd44b65b8ce386a920' 
  AND token = 'Y2mx+XrRXqXgLDb8PE3rSm/wBJndqzKSbPo0tLolX+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

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