SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd55ee1abe2529ee231085288eee6c175e3af42396d024665fc8545953253149a' 
  AND token = 'lZt6QHJ7zbaZRmwSkjEkISqj5p55wx06DkYV3LJ/9zo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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