mysql_select

<?php
$mtime = explode(' ', microtime());
$tstart = $mtime[1] + $mtime[0];
//////////////////////////////////

$link = mysql_connect('localhost', 'miha', 'qwerty');
mysql_select_db('mysql', $link);
mysql_query("set names utf8", $link);

for ($i = 0; $i < 1000; $i++)
{
    $s = mysql_query("SELECT * FROM `help_relation` WHERE `help_keyword_id` = $i", $link);
    echo 'rowCount: '.mysql_num_rows($s).'<br>';
}

//////////////////////////////////
$mtime = explode(' ', microtime());
$mtime = $mtime[1] + $mtime[0];
echo '<br><br>Time: '.round((($mtime - $tstart) * 1000), 4).' мс<br>';
?>