Here i am updating three meta attribute.But you can update any no of attribute as per your requirement.

ProductMetaImport.php

<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
ini_set('memory_limit', '512M');
require 'app/Mage.php';
umask(0);
Mage::app('default');

class ImportProductMeta extends Mage_Core_Model_Abstract {
	protected $_fileName;
	protected $_dbSKUArray;
	protected $_csvArray = array();
	public function _construct() {
		parent::_construct();
		$this->_initValue();

	}

	protected function _initValue() {
		$this->_fileName = 'MorganWright.csv';
		return $this;
	}

	public function importProductMetaStart() {
		$this->_createCSVDataArray();
    	$productCollection = Mage::getModel('catalog/product')->getCollection();

		foreach ($productCollection as $product) {
			$action = Mage::getModel('catalog/resource_product_action');
			$action->updateAttributes(array($product->getId()), $this->_dbSKUArray[$product->getSku()], 1);
            echo $product->getSku().' Updated successfully.';
            break;

		}

	}
	protected function _createCSVDataArray() {
		$this->_readcsvfile($this->_fileName);
		foreach ($this->_csvArray as $key => $dataArr) {
			$this->_dbSKUArray[$dataArr['Sku']] = array('meta_keyword' => '', 'meta_title' => $dataArr['Meta Title'], 'meta_description' => $dataArr['Meta Description']);
		}
	}

	protected function _readcsvfile($csvfileName) {
		$io = new Varien_Io_File();

		$path = Mage::getBaseDir('var') . DS . 'import';
		$file = $path . DS . $csvfileName;
		$io->open(array('path' => $path));
		$fileName = $io->getCleanPath($path . $file);
		$io->streamOpen($file, 'r+');

		$i = 0;

		$header = NULL;
		if (($handle = $io->streamReadCsv(',')) !== FALSE) {
			$handle = array_map('trim', $handle);
			$header = $handle;
			$this->_headers = $header;
			while (($data = $io->streamReadCsv(',')) !== FALSE) {
				if (!$header) {
					$header = $data;
				} else {
					$itemData = array_combine($header, $data);
					$this->_csvArray[] = $itemData;
				}
				$i++;
			}
		}
	}

}

$importObject = new ImportProductMeta();
$importObject->importProductMetaStart();