SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46f9ed17e9104632ec0d77dd2b29ac4a3b2137f22d44b92597a76799d606a83f' 
  AND token = 'AJspFKVzXfpMP3IrwUK1HaYnvfrTjdgGYphaYhMgD8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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