SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '07874b9a6553900105d48a3c8566e676288b719acefe514dee919a04d3b5fe0d' 
  AND token = 'Vm1r86PGjMMV2pxVKtKiU494QQalsSymk/j7P0TWrJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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