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 (
    92991, 92992, 92993, 92994, 92995, 92996, 
    92997, 92998, 92999, 93000, 93001, 
    93078, 93080, 93082, 93084, 93085, 
    93086, 93087, 93089, 93091, 93093, 
    93094, 93095, 93096, 93097, 93098, 
    93099, 93100, 93101, 93102, 93103, 
    93104, 93105, 93106, 93107, 93108, 
    93109, 93110, 93111, 93112, 93113, 
    93114, 93116, 93118, 93120, 93121, 
    93122, 93123
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00100

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 (92991,92992,92993,92994,92995,92996,92997,92998,92999,93000,93001,93078,93080,93082,93084,93085,93086,93087,93089,93091,93093,93094,93095,93096,93097,93098,93099,93100,93101,93102,93103,93104,93105,93106,93107,93108,93109,93110,93111,93112,93113,93114,93116,93118,93120,93121,93122,93123)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
92991
92992
92993
92994
92995
92996
92997
92998
92999
93000
93001
93078
93080
93082
93084
93085
93086
93087
93089
93091
93093
93094
93095
93096
93097
93098
93099
93100
93101
93102
93103
93104
93105
93106
93107
93108
93109
93110
93111
93112
93113
93114
93116
93118
93120
93121
93122
93123