Mysql – EXPLAIN output suggests that the index is not being used

I have set up my table with an index only on done_status(done_status = INT):

When I use:

EXPLAIN SELECT * FROM reminder  WHERE done_status=2

I get this back:

id  select_type  table     type  possible_keys  key  key_len  ref  rows  Extra
1   SIMPLE       reminder  ALL   done_status    NULL NULL     NULL 5     Using where

But when I issue this command:

EXPLAIN SELECT * FROM reminder  WHERE done_status=1

I get the following returned:

id  select_type  table     type  possible_keys  key          key_len  ref   rows  Extra
1   SIMPLE       reminder  ref   done_status    done_status  4        const 2   

The EXPLAIN shows me that it uses 5 rows, the second time 2 rows.

I don't think the index is used, if I understood it right first time it should give me 3 rows. What do I do wrong?

SHOW INDEX FROM reminder:

Table    Non_unique  Key_name     Seq_in_index  Column_name  Collation  Cardinality  Sub_part  Packed  Null  Index_type  Comment  Index_comment
reminder 1           done_status  1             done_status  A          5            NULL      NULL          BTREE

explain extended:

id  select_type  table     type  possible_keys  key          key_len  ref    rows  filtered  Extra
1   SIMPLE       reminder  ref   done_status    done_status  4        const  2     100.00

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