SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '86be32d13447ca5a80339e7930d264b2801a36cf802834385e9a796c73660283' 
  AND token = 'jfU0E57wFvxleXHWz4TSCbl7g2Fdy9AVnyFHQycv6cU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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