SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b47a0454aa89a4c7b12946b9539bef30cbe255b468e6282e6a416247ea683409' 
  AND token = 'sIhJ17/rwuD/qRq7PJverQPeRDQoHfDfeRKf37Xof90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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