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SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description, 
  cscart_product_descriptions.meta_keywords, 
  cscart_product_descriptions.meta_description, 
  cscart_product_descriptions.search_words, 
  cscart_product_descriptions.promo_text 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    21831, 18743, 12099, 12259, 12174, 12166, 
    12241, 11885, 11739, 11625, 11646, 
    11460, 11463, 10820, 10693, 10690, 
    10646, 10639, 10573, 10568
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00051

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	cscart_product_descriptions	range	PRIMARY,product_id	PRIMARY	9		20	Using where

Result

product_id	meta_keywords	meta_description	search_words
10568			YEAH049,Yeah Boi Recordings,Bowie666
10573			FLMBD010,Flammable Hard Dance,Matt E.B,Elivate
10639			DLI012,D'Licious,Dan Bentick,Djay D,Micky P,Ant Reynolds
10646			DNZ044,DNZ Records,Dj Oskar
10690			DLI011,D'Licious,Dan Bentick
10693			DLI011,D'Licious,K Finn,Matt Alliss
10820			AA004,Audio Abuse Recordings,Cliffy & Riggsy
11460			ACTD001,Active Sound Records,Bad Beast
11463	The Sound of Champions, Champion Sounds, Champion Sounds Remix, Smyrky, Seraya, Smyrky and Seraya, Smyrky & Seraya, Ruff Cut, Ruff Cut Digital, Hard House, Hard NRG, NRG, Hard Dance, Hard Trance, Hard Drive, Hard Dance Ibiza, Facebook, Av it	The Sound of Champions, Champion Sounds, Champion Sounds Remix, Smyrky, Seraya, Smyrky and Seraya, Smyrky & Seraya, Ruff Cut, Ruff Cut Digital, Hard House, Hard NRG, NRG, Hard Dance, Hard Trance, Hard Drive, Hard Dance Ibiza, Facebook, Av it	The Sound of Champions, Champion Sounds, Champion Sounds Remix, Smyrky, Seraya, Smyrky and Seraya, Smyrky & Seraya, Ruff Cut, Ruff Cut Digital, Hard House, Hard NRG, NRG, Hard Dance, Hard Trance, Hard Drive, Hard Dance Ibiza, Facebook, Av it
11625			DNZ051,DNZ Records,Rafa Dj,Dj Oskar
11646	hard house, nikkdbubble, sweaty hetty, mojo music	One for the Hardbeat fans as Nikk recreates BK's old skool offbeat to perfection! Get your grin out!	hard house, nikkdbubble, sweaty hetty, mojo music
11739			DNZ054,DNZ Records,Dj Oskar
11885			FLMBD018,Flammable Hard Dance,Sharp-E
12099			FLMBD023,Flammable Hard Dance,Ozy,Kye Shand
12166			FLMBD021,Flammable Hard Dance,Brickenden DJ's
12174			HNRS001,Hardnoise Records,Nando CP
12241			AA008,Audio Abuse Recordings,Riggsy,Michael James
12259			Cheek101,Cheeky Tracks,Discam,Klubfiller
18743			TPS001,TPS Records,Dj Crazybass
21831			Digital14,Cenobite Records,Damian