SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e6c9315cc2091e93b4b45aa3275f158a8d90c0da80a43713e0f17db9e164393' 
  AND token = 'cyoFcFOPz4z8Zs7aeeLAapZ5xwB3N5wyn7cPw4iNg6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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