SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '', 
    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 (
    1467, 1484, 1486, 1487, 1488, 1489, 1090, 
    1091, 1092, 1089, 1490, 1491, 962, 902, 
    1468, 903, 1469, 1470, 1471, 1492, 1493, 
    1494, 1495, 1496
  ) 
  AND cscart_product_descriptions.lang_code = 'ja'

Query time 0.00093

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "57.61"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "index_condition": "((`eshopuga_upgr_4122`.`cscart_product_descriptions`.`product_id` in (1467,1484,1486,1487,1488,1489,1090,1091,1092,1089,1490,1491,962,902,1468,903,1469,1470,1471,1492,1493,1494,1495,1496)) and (`eshopuga_upgr_4122`.`cscart_product_descriptions`.`lang_code` = 'ja'))",
      "cost_info": {
        "read_cost": "52.81",
        "eval_cost": "4.80",
        "prefix_cost": "57.61",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text"
      ]
    }
  }
}