SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35bb85b5ed7fdab2fa3c62795c8aad2a007f14c54cb9211f0a979667f658288f' 
  AND token = 'nJs08+64khk5wuWtfOgUnDC9HO7gB7b7oxXhyKTKzjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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