SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d164a560a495c4b611237787187e762c9b940899d7f1a861d613440befad7e4' 
  AND token = 'zP99TTi6p67PVTAcTqk6SOJfcl/2CkcHrUxsX8WqiXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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