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SELECT 
  SQL_CALC_FOUND_ROWS products.product_id, 
  IF(
    shared_descr.product_id IS NOT NULL, 
    shared_descr.product, descr1.product
  ) as product, 
  companies.company as company_name, 
  products.product_type, 
  products.parent_product_id, 
  products.free_shipping, 
  products.product_label_id, 
  products.product_label_id_by_admin, 
  categories.id_path 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'ru' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN cscart_ult_product_descriptions shared_descr ON shared_descr.product_id = products.product_id 
  AND shared_descr.company_id = 1 
  AND shared_descr.lang_code = 'ru' 
  LEFT JOIN cscart_categories as categories ON categories.category_id = products_categories.category_id 
  LEFT JOIN cscart_product_label as product_label ON product_label.id = products.product_label_id_by_admin 
WHERE 
  1 
  AND cscart_categories.category_id IN (245, 246, 247, 248, 249) 
  AND companies.status IN ('A') 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND products.parent_product_id = 0 
GROUP BY 
  products.product_id 
ORDER BY 
  product asc, 
  products.product_id ASC 
LIMIT 
  0, 48

Query time 0.00144

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	companies	system	PRIMARY				1	Using temporary; Using filesort
1	SIMPLE	cscart_categories	range	PRIMARY,c_status,p_category_id	PRIMARY	3		5	Using index condition; Using where
1	SIMPLE	products_categories	ref	PRIMARY,pt	PRIMARY	3	cscart_dev_4_16.cscart_categories.category_id	5	Using index
1	SIMPLE	prices	ref	usergroup,product_id,lower_limit,usergroup_id	usergroup	3	cscart_dev_4_16.products_categories.product_id	1	Using where; Using index
1	SIMPLE	products	eq_ref	PRIMARY,status,idx_parent_product_id	PRIMARY	3	cscart_dev_4_16.products_categories.product_id	1	Using where
1	SIMPLE	shared_descr	eq_ref	PRIMARY,product_id,company_id	PRIMARY	13	cscart_dev_4_16.products_categories.product_id,const,const	1	Using where
1	SIMPLE	categories	eq_ref	PRIMARY,p_category_id	PRIMARY	3	cscart_dev_4_16.cscart_categories.category_id	1
1	SIMPLE	descr1	eq_ref	PRIMARY,product_id	PRIMARY	9	cscart_dev_4_16.products_categories.product_id,const	1	Using where

Result

product_id	product	company_name	product_type	free_shipping	id_path
94	Batman: Arkham City (X360)	CS-Cart	P	N	245/248
96	Batman: Arkham City (X360) CE	CS-Cart	P	N	245/248
136	BlazBlue: Continuum Shift EXTEND	CS-Cart	P	N	245/249
90	F.E.A.R. 3 (PS3) MX	CS-Cart	P	N	245/247
95	Game Party: In Motion (X360)	CS-Cart	P	N	245/248
89	Green Lantern: Rise of the Manhunters (PS3)	CS-Cart	P	N	245/247
82	Legend of the Guardians: the Owls of Ga'hoole(VG)	CS-Cart	P	N	245/246
84	Lego Batman (Wii)	CS-Cart	P	N	245/246
85	Looney Tunes: Acme Arsenal (Wii)	CS-Cart	P	N	245/246
88	Lord of the Rings: War in the North(PS3)	CS-Cart	P	N	245/247
47	MARVEL® VS. CAPCOM® 3: FATE OF TWO WORLDS SPECIAL EDITION (PS3)	CS-Cart	P	N	245/247
138	Ridge Racer	CS-Cart	P	N	245/249
93	Scene It? Bright Lights! Big Screen(X360)	CS-Cart	P	N	245/248
87	Sesame Street:Cookie's Counting Carnival (Wii)	CS-Cart	P	N	245/246
139	Shinobido 2: Revenge of Zen	CS-Cart	P	N	245/249
83	Speed Racer: The Videogame (Wii)	CS-Cart	P	N	245/246
137	Ultimate Marvel VS. Capcom® 3	CS-Cart	P	N	245/249
248	X-Box One	CS-Cart	P	N	245/248