SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50bf4648d787ddc8599f03d3daa33d63861c7547416c90543cb56fa682433cde' 
  AND token = 'KNc/FFc+iqVOQQAeUX8fhn6GouYXhzZjFJ7tvdftM9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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