SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '37d0d979a620e381fe30ec69924486e620f040717b84aeba221ce781acb77c3b' 
  AND token = 'deV0a1QTZVtYBpArJCioF3kYFkGeARgKLmQ9a43eUXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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