SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7f82f4f13550d4c6d373dd75314681d5b95696486ec6e8d114885c296a8eef41' 
  AND token = 'Ksk+Hv/a803GvRcQ589s3RLJ4mbDujG4izk51OfFODw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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