SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0683a40e4ccf5514b55884268c2baa3766601b0c9a43a46390833f4bdddbee6d' 
  AND token = 'GycYVk8vMQLgdPo6G65lW32i0BTF05oX0QRBlHwdm4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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