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 (
    86637, 86706, 83184, 83189, 83165, 82829, 
    82902, 82975, 82607, 83198, 82610, 
    92603, 92604, 92605, 92606, 92607, 
    92608, 92609, 92610, 92611, 92612, 
    92613, 92614, 92615, 92616, 92617, 
    92618, 92619, 92626, 92627, 92628, 
    92629, 92630, 92631, 92632, 92633, 
    92634, 92635, 92636, 92637, 92638, 
    92639, 92640, 92641, 92642, 92649, 
    92650, 92651
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00098

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (86637,86706,83184,83189,83165,82829,82902,82975,82607,83198,82610,92603,92604,92605,92606,92607,92608,92609,92610,92611,92612,92613,92614,92615,92616,92617,92618,92619,92626,92627,92628,92629,92630,92631,92632,92633,92634,92635,92636,92637,92638,92639,92640,92641,92642,92649,92650,92651)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}