SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19b47180c9fd73b9811afa32a1d5469344314d44b3d5d86f8662a19f027ca1df' 
  AND token = 'PNpphYlApxSJSH7nkDKlJh46vzSdsgVWY3BAFw5gn+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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