SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ad4583ac40425d259b3e2d2d3987ee429d046f1770155a1cea021546e92094f' 
  AND token = 'IlU0K+Lnwam4JRMOJMrdOKstmNIc+OwMmEK/YReexDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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