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 (
    100775, 100776, 100777, 100778, 100779, 
    100780, 100781, 100782, 100783, 100784, 
    100785, 100786, 100787, 100788, 100789, 
    100790, 100791, 100792, 100793, 100794, 
    100795, 100796, 100797, 100798, 100799, 
    100800, 100801, 100802, 100803, 100804, 
    100805, 100806, 100807, 100808, 100809, 
    100810, 100811, 100812, 100813, 100814, 
    100815, 100816, 100817, 100818, 100819, 
    100820, 100821, 100822, 100823, 100824, 
    100825, 100826, 100827, 100828, 100829, 
    100830, 100831, 100832, 100833, 100834, 
    100835, 100836, 100837, 100838, 100839, 
    100840, 100841, 100842, 100843, 100844, 
    100845, 100846, 100847, 100848, 100856, 
    100879, 100880, 100881, 100882, 100883, 
    100888, 100889, 100890, 100891, 100892, 
    100893, 100894, 100895, 100896, 100897, 
    100898, 100899, 100905, 100906, 100911, 
    100912
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00149

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "43.24"
    },
    "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": 96,
      "rows_produced_per_join": 96,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "33.64",
        "eval_cost": "9.60",
        "prefix_cost": "43.24",
        "data_read_per_join": "366K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (100775,100776,100777,100778,100779,100780,100781,100782,100783,100784,100785,100786,100787,100788,100789,100790,100791,100792,100793,100794,100795,100796,100797,100798,100799,100800,100801,100802,100803,100804,100805,100806,100807,100808,100809,100810,100811,100812,100813,100814,100815,100816,100817,100818,100819,100820,100821,100822,100823,100824,100825,100826,100827,100828,100829,100830,100831,100832,100833,100834,100835,100836,100837,100838,100839,100840,100841,100842,100843,100844,100845,100846,100847,100848,100856,100879,100880,100881,100882,100883,100888,100889,100890,100891,100892,100893,100894,100895,100896,100897,100898,100899,100905,100906,100911,100912)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}