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 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    96549, 96550, 96551, 96552, 96553, 96554, 
    96555, 96556, 96557, 96558, 96562, 
    96563, 96569, 96601, 96602, 96603, 
    96604, 96605, 96606, 96607, 96608, 
    96609, 96610, 96611, 96612, 96613, 
    96614, 96615, 96616, 96617, 96618, 
    96619, 96620, 96621, 96622, 96623, 
    96624, 96625, 96626, 96627, 96628, 
    96629, 96630, 96631, 96632, 96633, 
    96634, 96635
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00095

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "26.16"
    },
    "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",
      "cost_info": {
        "read_cost": "21.36",
        "eval_cost": "4.80",
        "prefix_cost": "26.16",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (96549,96550,96551,96552,96553,96554,96555,96556,96557,96558,96562,96563,96569,96601,96602,96603,96604,96605,96606,96607,96608,96609,96610,96611,96612,96613,96614,96615,96616,96617,96618,96619,96620,96621,96622,96623,96624,96625,96626,96627,96628,96629,96630,96631,96632,96633,96634,96635)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}