SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4a680e7f8fc646b402b36fc26df6590af96f680caae87f1b1aca9dce53a9538f' 
  AND token = '+YyGQ+MsFgQqduHF6bol3U1ffkUvz1hPLk/5jrjYWnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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