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 (
    588450, 588454, 594298, 588407, 588439, 
    588446, 588502, 594366, 588429, 588478
  ) 
  AND cscart_product_descriptions.lang_code = 'ro'

Query time 0.00130

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.01"
    },
    "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": 10,
      "rows_produced_per_join": 10,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "11.02",
        "eval_cost": "1.00",
        "prefix_cost": "12.02",
        "data_read_per_join": "38K"
      },
      "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 (588450,588454,594298,588407,588439,588446,588502,594366,588429,588478)) and (`maniamall_cscart`.`cscart_product_descriptions`.`lang_code` = 'ro'))"
    }
  }
}

Result