SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6af255a75ad9cf477eb976b5662efe600a779ef2489ea82da0a037805ccc72f8' 
  AND token = 'EHUJEDeo5XIs7j7mWdCWI4HUzGS/cwGNlhANmCsjjE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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