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SELECT 
  pf.feature_id, 
  pf.company_id, 
  pf.feature_type, 
  pf.parent_id, 
  pf.display_on_product, 
  pf.display_on_catalog, 
  pf.display_on_header, 
  cscart_product_features_descriptions.description, 
  cscart_product_features_descriptions.lang_code, 
  cscart_product_features_descriptions.prefix, 
  cscart_product_features_descriptions.suffix, 
  pf.categories_path, 
  cscart_product_features_descriptions.full_description, 
  pf.status, 
  pf.comparison, 
  pf.position 
FROM 
  cscart_product_features AS pf 
  LEFT JOIN cscart_product_features_descriptions ON cscart_product_features_descriptions.feature_id = pf.feature_id 
  AND cscart_product_features_descriptions.lang_code = 'en' 
  INNER JOIN cscart_ult_objects_sharing ON (
    cscart_ult_objects_sharing.share_object_id = pf.feature_id 
    AND cscart_ult_objects_sharing.share_company_id = 1 
    AND cscart_ult_objects_sharing.share_object_type = 'product_features'
  ) 
WHERE 
  pf.feature_type = 'G' 
  AND (
    pf.feature_id IN ('') 
    OR pf.feature_id NOT IN (
      SELECT 
        parent_id 
      FROM 
        cscart_product_features
    )
  ) 
ORDER BY 
  pf.position, 
  cscart_product_features_descriptions.description

Query time 0.00106

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	pf	ALL	PRIMARY				91	Using where; Using temporary; Using filesort
1	PRIMARY	cscart_product_features_descriptions	eq_ref	PRIMARY	PRIMARY	9	mahm3t_cs443.pf.feature_id,const	1	Using where
1	PRIMARY	cscart_ult_objects_sharing	eq_ref	PRIMARY	PRIMARY	159	mahm3t_cs443.pf.feature_id,const,const	1	Using where; Using index
2	MATERIALIZED	cscart_product_features	ALL					91

Result

feature_id	company_id	feature_type	parent_id	display_on_product	display_on_catalog	display_on_header	description	lang_code	prefix	suffix	categories_path	full_description	status	comparison	position
150	1	G	0	N	N	N	Insulation fixings	en			471		A	N	100