SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '460788530b91de40aef0654047caf0c1f7efb4a11aea58b862372718c2185595' 
  AND token = 'hwCwyipXLskzCjXPiS0C1If+t3d2NSxWXxUhIJDdZzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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