SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  cscart_product_descriptions.full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    65436, 65438, 65439, 65440, 65441, 65442, 
    65443, 65444, 65445, 65446, 65447, 
    65448
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.62"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id",
        "idx_product_desc_lang",
        "idx_product_name_search",
        "idx_product_desc_sort"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 12,
      "rows_produced_per_join": 12,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "9.42",
        "eval_cost": "1.20",
        "prefix_cost": "10.62",
        "data_read_per_join": "54K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`cscart_db`.`cscart_product_descriptions`.`product_id` in (65436,65438,65439,65440,65441,65442,65443,65444,65445,65446,65447,65448)) and (`cscart_db`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}