//我只能想到foreach方式咯,欢迎大神修改
$data = [
    '2020-02-02 11:11:11',
    '2019-02-02 11:55:11',
    '2018-12-02 11:33:11',
    '2017-12-02 11:22:11',
];

$near = array_reduce($data, function($a, $b){
   return abs((time() - strtotime($a))) < abs((time() - strtotime($b))) ? $a : $b;
});

echo $near;