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 (
    430695, 430988, 430644, 431073, 431083, 
    431313, 430628, 430730, 431043, 431135, 
    430842, 430844, 431063, 431089, 431167, 
    431183, 431459, 339831, 430829, 430651, 
    430662, 430880, 430884, 431066, 430869, 
    430898, 430899, 430928, 339762, 430769, 
    430962, 431142, 339781, 430684, 431035, 
    430653, 430712, 430847, 430891, 431140, 
    430631, 430893, 430626, 431185, 381713, 
    431031, 431093, 430881, 430896, 430909, 
    431123, 339733, 339691, 430806, 430883, 
    431197, 430633, 430797, 430900, 430980, 
    431250, 339600, 430873, 431088, 431226, 
    430837, 430787, 430876, 430930, 431023, 
    430645, 430685, 430758, 430913, 431064, 
    339804, 430676, 430768, 430772, 431119, 
    431121, 339488, 430760, 430841, 430981, 
    431008, 431078, 431131, 431198, 339594, 
    430796, 430802, 430846, 431032, 431113, 
    431159, 431178, 431356, 430698, 430703
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00215

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "140.18"
    },
    "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": 100,
      "rows_produced_per_join": 100,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "120.18",
        "eval_cost": "20.00",
        "prefix_cost": "140.18",
        "data_read_per_join": "682K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (430695,430988,430644,431073,431083,431313,430628,430730,431043,431135,430842,430844,431063,431089,431167,431183,431459,339831,430829,430651,430662,430880,430884,431066,430869,430898,430899,430928,339762,430769,430962,431142,339781,430684,431035,430653,430712,430847,430891,431140,430631,430893,430626,431185,381713,431031,431093,430881,430896,430909,431123,339733,339691,430806,430883,431197,430633,430797,430900,430980,431250,339600,430873,431088,431226,430837,430787,430876,430930,431023,430645,430685,430758,430913,431064,339804,430676,430768,430772,431119,431121,339488,430760,430841,430981,431008,431078,431131,431198,339594,430796,430802,430846,431032,431113,431159,431178,431356,430698,430703)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}