SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b2a352332f007d513c9f13d177b389cd1e0657a12e843c5d67cab476c73cf7f' 
  AND token = 'IGfOQe0LmNao4wqELgU/eKSzIuf9djmHFwq+XqU+kg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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