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 (
    1231165, 2382470, 1129861, 1231521, 
    1338884, 1231908, 1232078, 1231479, 
    1231470, 1731742, 1231132, 1231691, 
    1231415, 1877564, 1231619, 1231444, 
    1232132, 1129864, 1232130, 1231628, 
    1231934, 1282939, 1232067, 2382443, 
    1732098, 1232255, 1231180, 1232536, 
    1232342, 1283561, 1162823, 1231062, 
    2538988, 1231689, 2068218, 1231061
  ) 
  AND cscart_product_descriptions.lang_code = 'ro'

Query time 0.00156

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "43.08"
    },
    "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": 36,
      "rows_produced_per_join": 36,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "39.48",
        "eval_cost": "3.60",
        "prefix_cost": "43.08",
        "data_read_per_join": "137K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text"
      ],
      "attached_condition": "((`maniamall_cscart`.`cscart_product_descriptions`.`product_id` in (1231165,2382470,1129861,1231521,1338884,1231908,1232078,1231479,1231470,1731742,1231132,1231691,1231415,1877564,1231619,1231444,1232132,1129864,1232130,1231628,1231934,1282939,1232067,2382443,1732098,1232255,1231180,1232536,1232342,1283561,1162823,1231062,2538988,1231689,2068218,1231061)) and (`maniamall_cscart`.`cscart_product_descriptions`.`lang_code` = 'ro'))"
    }
  }
}

Result