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 (
    12684, 12714, 13260, 13267, 12349, 12364, 
    12259, 12504, 12524, 12379, 6843, 6840, 
    6841, 6846, 13274, 13286, 13280, 13292, 
    6962, 6966, 6967, 6965, 6963, 6952, 
    6953, 3484, 3487, 3485, 3486, 6969, 
    3434, 6947, 3424, 3911, 3422, 3910, 
    3421, 3909, 3420, 3423, 3912, 3430, 
    3429, 3437, 3436, 3438, 6959, 3425
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00130

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "48.49"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "index_condition": "((`test2_gaseus`.`cscart_product_descriptions`.`product_id` in (12684,12714,13260,13267,12349,12364,12259,12504,12524,12379,6843,6840,6841,6846,13274,13286,13280,13292,6962,6966,6967,6965,6963,6952,6953,3484,3487,3485,3486,6969,3434,6947,3424,3911,3422,3910,3421,3909,3420,3423,3912,3430,3429,3437,3436,3438,6959,3425)) and (`test2_gaseus`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "43.69",
        "eval_cost": "4.80",
        "prefix_cost": "48.49",
        "data_read_per_join": "219K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "meta_keywords",
        "meta_description",
        "search_words",
        "promo_text",
        "unit_name"
      ]
    }
  }
}