Сергей Пуговкин

return [
    'timeZone' => 'Europe/Minsk',
    'components' => [
        'formatter' => [  
            'dateFormat' => 'd.MM.yyyy',
            'timeFormat' => 'H:mm:ss',
            'datetimeFormat' => 'd.MM.yyyy H:mm',
        ],
    ],
];

Yii::$app->getFormatter()->asDate(time());
Yii::$app->getFormatter()->asDatetime(time())

<?= GridView::widget([
        'dataProvider' => $dataProvider,
        'columns' => [
            'created_at:datetime',
        ],
]); ?>