mysql> INSERT INTO custom_wifi_score( user_id, 
    -> TYPE , iblock_element_id, score ) 
    -> VALUES ( 517049460113,  'OK', 30033, 20 );
ERROR 1062 (23000): Duplicate entry '30033-OK-2147483647' for key 'unique_index'

mysql> show index from custom_wifi_score where key_name='unique_index'\G
*************************** 1. row ***************************
        Table: custom_wifi_score
   Non_unique: 0
     Key_name: unique_index
 Seq_in_index: 1
  Column_name: iblock_element_id
    Collation: A
  Cardinality: 316
     Sub_part: NULL
       Packed: NULL
         Null: 
   Index_type: BTREE
      Comment: 
Index_comment: 
*************************** 2. row ***************************
        Table: custom_wifi_score
   Non_unique: 0
     Key_name: unique_index
 Seq_in_index: 2
  Column_name: type
    Collation: A
  Cardinality: 702
     Sub_part: NULL
       Packed: NULL
         Null: 
   Index_type: BTREE
      Comment: 
Index_comment: 
*************************** 3. row ***************************
        Table: custom_wifi_score
   Non_unique: 0
     Key_name: unique_index
 Seq_in_index: 3
  Column_name: user_id
    Collation: A
  Cardinality: 6322
     Sub_part: NULL
       Packed: NULL
         Null: 
   Index_type: BTREE
      Comment: 
Index_comment: 
3 rows in set (0.01 sec)