SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8424f32709340028b4ba1629fe7ab6607cd4231d8cd15235a54187ae1eb91b6' 
  AND token = 'EMy2F4vQ4MkG7hY1xZFlH6bC/29RTlvqS9Ruusy2DHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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