SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64ec526f5478a56996cf2e1d2868faa6ee1761ffab54ed6eb2e4a8804db9b657' 
  AND token = 'WPVzcnnAXohHZxJUAWyjDSBK728yTnbJGNCDKM1yIwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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