SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '590fce65266b5346301dcc4315b9746658b383a082c0651c77ef317c84d7d648' 
  AND token = 'KCjKRdbWpyy+qP21MPltNYTQDd+GE4AfChdmbrJ0IEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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