Test

<?php
//https://codepen.io/SimoTod/pen/RwNYNXm
$str_needle = 's6tbdfgj222dJGk';
$str_seed = str_repeat("0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", 10);

foreach ([10000, 1000, 100, 10] as $int_number_of_item) {
    echo "N={$int_number_of_item}\n";

    //Populate array
    $arr_heystack = [];
    for ($int_counter = 0; $int_counter < $int_number_of_item; $int_counter++) {
        $arr_heystack[] = substr(str_shuffle($str_seed), 0, rand(10, 100));;
    }

    //benchmarks
    $int_time = microtime(1);
    $mix_test = in_array($str_needle, $arr_heystack);
    echo "in_array:     ", number_format(microtime(1) - $int_time, 10), PHP_EOL;

    $int_time = microtime(1);
    $mix_test = array_search($str_needle, $arr_heystack);
    echo "array_search: ", number_format(microtime(1) - $int_time, 10), PHP_EOL;

    $int_time = microtime(1);
    $arr_heystack = array_flip($arr_heystack);
    $mix_test = isset($arr_heystack[$str_needle]);
    echo "flip+isset:   ", number_format(microtime(1) - $int_time, 10), PHP_EOL;
    echo PHP_EOL;
}