SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2282d86fd06d146cf4154853108d3583a4aa380eeae27d55667066b3f4f60cde' 
  AND token = 'YUCh8fQFqv322cERrZEOriyruI60J3jqV88IxdC4ruA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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