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 (
    74, 1161, 75, 374, 800, 1136, 224, 795, 
    1839, 797, 798, 1409, 367, 1393, 484, 
    445, 157, 388, 585, 241, 629, 590, 860, 
    1790, 230, 413, 681, 393, 1461, 60, 370, 
    1752, 1744, 934, 1010, 197
  ) 
  AND cscart_product_descriptions.lang_code = 'ja'

Query time 0.00132

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": 36,
      "filtered": 100,
      "index_condition": "cscart_product_descriptions.product_id in (74,1161,75,374,800,1136,224,795,1839,797,798,1409,367,1393,484,445,157,388,585,241,629,590,860,1790,230,413,681,393,1461,60,370,1752,1744,934,1010,197) and cscart_product_descriptions.lang_code = 'ja'"
    }
  }
}

Result

product_id short_description full_description meta_keywords meta_description search_words promo_text unit_name
60
74
75
157
197
224
230
241
367
370
374
388
393
413
445
484
585
590
629
681
795
797
798
800
860
934
1010
1136
1161
1393
1409
1461
1744
1752
1790
1839