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 (
    94784, 94785, 94786, 94787, 94788, 94789, 
    94790, 94791, 94792, 94793, 94794, 
    94795, 94814, 94815, 94833, 94834, 
    94835, 94836, 94837, 95443, 95444, 
    95445, 95446, 95447, 95791, 95792, 
    95793, 95794, 95795, 95796
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00085

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (94784,94785,94786,94787,94788,94789,94790,94791,94792,94793,94794,94795,94814,94815,94833,94834,94835,94836,94837,95443,95444,95445,95446,95447,95791,95792,95793,95794,95795,95796)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94784
94785
94786
94787
94788
94789
94790
94791
94792
94793
94794
94795
94814
94815
94833
94834
94835
94836
94837
95443
95444
95445
95446
95447
95791
95792
95793
95794
95795
95796