SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ff16d2b9b567a695b440db1f54d16c56d394c359bed5e2a2b817daec7de16769' 
  AND token = 'lsS9zgPPQhyJEE4S0Af9jmrlrZOms8215+KuvMGty38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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