In MySQL column, how do I only allow data that matches a certain pattern?

I am using a current version of MySQL

I have created a table:

CREATE  TABLE IF NOT EXISTS `Uniq_Entity` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `ein` VARCHAR (50) NULL  ,
  UNIQUE KEY `uq_ein` (ein)
)
ENGINE = InnoDB;

I just was asked to prevent the ein field from having any value other than this pattern:

[0-9a-zA-Z]{18}[0-9]{2}

We are importing the data from a csv file using LOAD DATA LOCAL INFILE .

How do I modify the CREATE TABLE so any attempt to INSERT or UPDATE ein with data that does not match this pattern gets rejected?

Alternatively, how would I modify the INSERT or UPDATE query that would ignore any field that fails to match?

Thanks in advance!