Your customer has implemented a solution using Cloud Spanner and is experiencing read latency-related performance issues on a specific table. This table is accessed solely by their users via a primary key. The table's schema is as follows:

CREATE TABLE Persons (
  person_id INT64 NOT NULL,     // sequential number based on number of registrations
  account_creation_date DATE,   // system date
  birthdate DATE,               // customer birthdate
  firstname STRING (255),       // first name
  lastname STRING (255),        // last name
  profile_picture BYTES (255)   // profile picture
) PRIMARY KEY (person_id)

What action should you take to resolve the performance issue?