SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbd9985b4e155abf839afca46f75b9bd3ce8376e171108a4eee842b923cff78' 
  AND token = 'mVItDUufoWlOeVNO8oYvFDxeFcD2KsyDXrV670PrEfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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