Get Post By post_name

$post_name = 'my-post';

$querystr = 'SELECT * FROM "wp_posts" WHERE "post_name" = "' $post_name . '"';

$results = $wpdb->get_results($querystr, OBJECT);


if(!empty($results)) {
	foreach ($results as $result) {
		// do your magic
		break;
	}
} else {
	echo 'post '. $post_name . ' was not found.';
}

// see: https://codex.wordpress.org/Displaying_Posts_Using_a_Custom_Select_Query