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, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    12885, 12887, 12888, 12883, 12890, 12878, 
    12881, 12886, 12892, 12893, 12894, 
    12896, 12899, 12901, 12902, 12903, 
    12905, 12895, 12897, 12898
  ) 
  AND cscart_product_descriptions.lang_code = 'kk'

Query time 0.00062

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "product_id"],
      "key": "PRIMARY",
      "key_length": "9",
      "used_key_parts": ["product_id", "lang_code"],
      "rows": 20,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (12885,12887,12888,12883,12890,12878,12881,12886,12892,12893,12894,12896,12899,12901,12902,12903,12905,12895,12897,12898) and cscart_product_descriptions.lang_code = 'kk'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
12878
12881
12883
12885
12886
12887
12888
12890
12892
12893
12894
12895
12896
12897
12898
12899
12901
12902
12903
12905