SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86ab1604ac10050dcc0ea86dbd2086e0937e255e67e4382727d7f9da344ca12c' 
  AND token = 'azqE5xzrcp1wOEbDxwn9XDJ15H5S5Rovp6TdqVWFhrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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