SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6d03234f9f69e1f3b51ffd91f93a979890a08f49e44586a42e33989ab42752f' 
  AND token = 'Pv5/3tKJoFX2cqkAh6XNb6NDONYaeBOTAkKX0r2CC4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

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