SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '474f07ddadcd4c7dad3306a3a498f51435c24a5ba9a2fe426501319f464dfac3' 
  AND token = '0VgZ8648BPuvDNa1qRN+2ea/djA5ZohYOzkAozjtChU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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