SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '07c4be43cd016600af726c43214692ffca0608a1bafe580bea1506945f452874' 
  AND token = 'pDGljlTV1mn8MqmB0iQcIUWulC0xIHiKXmqHCZ/rSHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}