SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21dff27945df922030ef37fe727e5d98e3b885e5b1d67cdc3699346dcec23d07' 
  AND token = 'ESeJZCo0+jNCjmVSZDOih9ILu2MjKcV8/7KJliGcyzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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