SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29b6ad6211bf83a30df9d7380ca0f77215347d6aedbb3e72c0bcde1f90e5b59f' 
  AND token = '/PFhJNB9ZVbosqIbpYy5ZAkB+VuOIiq+6ywQjVhz+es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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