SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3de8028dd7438e266bde5ffa96c5eeaf2a2f7a8310e17dd293bb6a274284f87a' 
  AND token = 'Z7kqPi9iFwY/DMYlJYGLlJJ/eFZEbsPpRo+NHodg9KA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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