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 (
    100716, 100717, 100718, 100719, 100720, 
    100721, 100722, 100723, 100724, 100725, 
    100726, 100727, 100728, 100729, 100730, 
    100731, 100732, 100733, 100734, 100735, 
    100736, 100737, 100738, 100739, 100740, 
    100741, 100742, 100743, 100744, 100745, 
    100746, 100747, 100748, 100749, 100750, 
    100751, 100752, 100753, 100754, 100755, 
    100756, 100757, 100758, 100759, 100760, 
    100761, 100762, 100763, 100764, 100765, 
    100766, 100767, 100768, 100769, 100770, 
    100771, 100772, 100773, 100774, 100775, 
    100776, 100777, 100778, 100779, 100780, 
    100781, 100782, 100783, 100784, 100785, 
    100786, 100787, 100788, 100841, 100842, 
    100843, 100844, 100845, 100846, 100847, 
    100848, 100856
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00125

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "36.94"
    },
    "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": 82,
      "rows_produced_per_join": 82,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "28.74",
        "eval_cost": "8.20",
        "prefix_cost": "36.94",
        "data_read_per_join": "312K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (100716,100717,100718,100719,100720,100721,100722,100723,100724,100725,100726,100727,100728,100729,100730,100731,100732,100733,100734,100735,100736,100737,100738,100739,100740,100741,100742,100743,100744,100745,100746,100747,100748,100749,100750,100751,100752,100753,100754,100755,100756,100757,100758,100759,100760,100761,100762,100763,100764,100765,100766,100767,100768,100769,100770,100771,100772,100773,100774,100775,100776,100777,100778,100779,100780,100781,100782,100783,100784,100785,100786,100787,100788,100841,100842,100843,100844,100845,100846,100847,100848,100856)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}