<?php
$array = [
    ['ts' => 3],
    ['ts' => 5],
    ['ts' => 1],
    ['ts' => 2],
    ['ts' => 7],
    ['ts' => 0],
];

usort($array, function($a, $b) {
    return $a['ts'] - $b['ts'];
});

var_dump($array);