SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0cb884657bf77692af832f9c4f15b8e40dbac2ca8d97678a38f55d900a3af85' 
  AND token = 'cbxi7pY6woEGHZP2m1YSCz6R+syn/gGRDUIOQzsz9k8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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