SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eaf3f69813efa090400f98ba791fd2e54e916d53dedd6ee4b9bd3ddf4fd305f' 
  AND token = 'YEgQ4FxqiPVf7QgNjkKK02OUTLhEMGCEE0SL9/0jFPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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