SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34a9cc6f44d5230f0a19519cc89b742729355fe8be9edcde3ec18903fdb55235' 
  AND token = 'hVwhOBzK3DLL228mJ86WiCzVOCEK+tE2pc7QyuWWlZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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