SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23721bb950f4dea29075a32b827333fc5071ff84eda91bcc8539ba05ee3f722' 
  AND token = '6EewGkLfibymp6gDSQ/4az9aQyN7k75+fkq1ig4RcEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}