SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58f08157a33dbef5c09f93d67ebec36247651bb7f09ebf624e37c6d9d3d6e238' 
  AND token = 'U1gWIYn8NumH+Z7hGeUQMZQtDAYjgSnZVKPcUBEEpgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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