SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c458cc6b546340f88fcaf43d55e9c2df31b95f6496fc8dce7010a4fe4375795f' 
  AND token = '3BSJYIaqFW5Dx5VlaRvBhuCTG3IHCTtLW+Ovw5FSlY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}