SELECT 
  q_product_descriptions.product_id, 
  q_product_descriptions.short_description, 
  IF(
    q_product_descriptions.short_description = '', 
    q_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  q_product_descriptions 
WHERE 
  q_product_descriptions.product_id IN (
    2913, 2914, 2915, 2916, 2917, 2918, 2919, 
    2920, 2921, 2881, 2882, 2883, 2884, 
    2885, 2886, 2887, 2888, 2889, 2890, 
    2891, 2892, 2858, 2859, 2860, 2861, 
    2862, 2863, 2864, 2865, 2866
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00082

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "72.01"
    },
    "table": {
      "table_name": "q_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",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (2913,2914,2915,2916,2917,2918,2919,2920,2921,2881,2882,2883,2884,2885,2886,2887,2888,2889,2890,2891,2892,2858,2859,2860,2861,2862,2863,2864,2865,2866)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "66.01",
        "eval_cost": "6.00",
        "prefix_cost": "72.01",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}