SELECT 
  lang.name, 
  IF(
    cscart_ult_language_values.value IS NULL, 
    lang.value, cscart_ult_language_values.value
  ) as value 
FROM 
  cscart_language_values lang 
  LEFT JOIN cscart_ult_language_values ON cscart_ult_language_values.name = lang.name 
  AND company_id = 2 
  AND cscart_ult_language_values.lang_code = lang.lang_code 
WHERE 
  lang.lang_code = 'en' 
  AND lang.name IN (
    'popup_cookie_header', 'popup_cookie_text', 
    'popup_cookie_analytics', 'cscart_cookies', 
    'google_analytics', 'facebook_tracking', 
    'adwords_tracking', 'skroutz_tracking', 
    'addthis_tracking', 'glami_tracking', 
    'yes_to_all', 'popup_cookie_deny', 
    'or_choose_what_to_enable', 'popup_cookie_agree', 
    'popup_cookie_header', 'popup_cookie_text', 
    'popup_cookie_analytics', 'cscart_cookies', 
    'google_analytics', 'facebook_tracking', 
    'adwords_tracking', 'skroutz_tracking', 
    'addthis_tracking', 'glami_tracking', 
    'yes_to_all', 'popup_cookie_deny', 
    'or_choose_what_to_enable', 'popup_cookie_agree'
  )

Query time 0.00058

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE lang range PRIMARY PRIMARY 392 14 Using index condition
1 SIMPLE cscart_ult_language_values eq_ref PRIMARY PRIMARY 396 mahm3t_cs443.lang.lang_code,mahm3t_cs443.lang.name,const 1

Result

name value
adwords_tracking Adwords tracking
cscart_cookies Necessary cookies
facebook_tracking Facebook tracking
google_analytics Google analytics
or_choose_what_to_enable or choose what to enable
popup_cookie_agree I Agree
popup_cookie_analytics Analytical cookies for us to better craft the user experience based on your page view experiences.
popup_cookie_deny Deny
popup_cookie_header Cookie policy
popup_cookie_text This site uses cookies to store information on your computer. See our <a href="[cookie_policy_url]">cookie policy</a> for further details on how to block cookies.
skroutz_tracking Skroutz tracking
yes_to_all Yes to all