SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '299c7a8256c415be1f772175b3d7ea3247156f4ba2f66010d2769a2a60489345' 
  AND token = 'XV1SnZnIaNQJzExnTpUEDkXcquI5zyfNTFbj64B5mD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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