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 (
    98502, 98882, 98883, 98884, 98885, 99068, 
    99069, 99070, 99071, 99072, 99073, 
    99074, 99075, 99076, 99077, 99078, 
    99079, 99080, 99081, 99082, 99083, 
    99084, 99085, 99086, 99087, 99088, 
    99089, 99090, 99091, 99092, 99093, 
    99094, 99095, 99096, 99097, 99098, 
    99099, 99100, 99101, 99102, 99103, 
    99104, 99105, 99106, 99107, 99108, 
    99109, 99114
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00151

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "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 (98502,98882,98883,98884,98885,99068,99069,99070,99071,99072,99073,99074,99075,99076,99077,99078,99079,99080,99081,99082,99083,99084,99085,99086,99087,99088,99089,99090,99091,99092,99093,99094,99095,99096,99097,99098,99099,99100,99101,99102,99103,99104,99105,99106,99107,99108,99109,99114)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98502
98882
98883
98884
98885
99068
99069
99070
99071
99072
99073
99074
99075
99076
99077
99078
99079
99080
99081
99082
99083
99084
99085
99086
99087
99088
99089
99090
99091
99092
99093
99094
99095
99096
99097
99098
99099
99100
99101
99102
99103
99104
99105
99106
99107
99108
99109
99114