SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959800a8ba6aa543af7914470366f6de017af08792081cda54b27f2279964375' 
  AND token = '4Hv+M32oZGjjOPrKuMrLwxnJtoRZLOPlAWfwd+XYiAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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