User.php

class User extends EloquentUser implements AuthenticatableContract, AuthorizableContract, CanResetPasswordContract
{
    use Authenticatable, Authorizable, CanResetPassword, Eloquence;

    /**
     * The database table used by the model.
     *
     * @var string
     */
    use SoftDeletes;
    protected $dates = ['deleted_at'];
    protected $table = 'users';

MySQL

mysql> select id,username,email from users where email='silver';
+-----+----------+--------+
| id  | username | email  |
+-----+----------+--------+
| 166 | si91msn  | silver |
+-----+----------+--------+
1 row in set (0.00 sec)

Tinker

>>> $user_id = User::where('email', '=', 'silver')->first(['id']);
=> null
>>>

What the heck is going on?