Filtering custom posts by custom fields (ACF) [closed]

Ok, so after deeper research I’ve found out that values of some custom fields created by ACF are stored in MySQL database with some additional information like a:5:{i:0;s:6:"Aerial";i:1;s:6:"Nature";i:2;s:4:"Nude";i:3;s:6:"People";i:4;s:8:‌​"Wildlife";}. This happens when a custom field can store multiple values (like chechboxes).

So I’ve edited part of my query from this:
if( !empty($_GET[‘theme’]) )
{
$contestTheme = explode(‘,’, $_GET[‘theme’]);

    $contestThemeArray = array(
        'key'       => 'theme',
        'value'     => $contestTheme,
        'compare'   => 'IN',
    );
}

To this:

if( !empty($_GET['contest_theme']) )
{
    $contestTheme = explode(',', $_GET['contest_theme']);
    $contestThemeArray = array('relation' => 'OR');
    foreach ($contestTheme as $theme) {
        $contestThemeArray[] = array(
            'key'       => 'contest_theme',
            'value'     => $theme,
            'compare'   => 'LIKE',
        );
    }

}