For all the RDBMS, Database Statistics are playing the main role to generate an accurate Query Execution Plan.
A Database Administrator is also very much responsible to make sure that Database Statistics is updated.

MySQL query optimizer is also preparing Query Execution Plan with the help of Statistics Information.
The auto-update Statistics configuration is also very important to keep Statistics updated.

How to enable auto-update Statistics for InnoDB engine?

We can configure innodb_stats_on_metadata variable to enable auto-update Statistics.

When this variable is enabled InnoDB updates statistics when metadata statements such as SHOW TABLE STATUS or SHOW INDEX are run, or when accessing the INFORMATION_SCHEMA.TABLES or INFORMATION_SCHEMA.STATISTICS tables.

Check innodb_stats_on_metadata is ON or OFF:

SHOW VARIABLES LIKE 'innodb_stats_on_metadata';

If innodb_stats_on_metadata is OFF, make it ON:

SET GLOBAL innodb_stats_on_metadata=ON;

When you perform command like SHOW INDEX, Statisitcs will be update.
Accuracy of statistics is depends on MySQL Server Load.

SHOW INDEXES FROM SchemaName.TableName;

You can use below query to check the Index Statistics:

SELECT 
    Table_Schema
    ,Table_Name
    ,Non_Unique
    ,Index_Schema
    ,Seq_In_Index
    ,Column_Name
    ,Collation
    ,Cardinality
    ,Index_Type
FROM information_schema.statistics 
WHERE TABLE_SCHEMA='SchemaName';

In this post, I am sharing one script to find Outdated Index Statistics of SQL Server.

Database Statistics are playing the main role to prepare a best query execution plan because Query Optimizer reads the Object Statistics and takes the decision accordingly.

SQL Server Statistics stores information like: object meta-data, location information, number of records.
If your Object Statistics are not updated, It impacts your query performance so You should find outdated statistics and periodically, you should update the statistics data.

SQL Server:Warning in Query Execution Plan, “Operator used tempdb to spill data during execution with spill level 2”

Script to find Outdated Index Statistics Information:

SELECT 
	OBJECT_NAME(id)
	,name
	,STATS_DATE(id, indid)
	,rowmodctr
FROM sys.sysindexes
WHERE STATS_DATE(id, indid)<=DATEADD(DAY,-1,GETDATE()) 
AND rowmodctr>0 
AND id IN (SELECT object_id FROM sys.tables)
GO