SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66cfbde00a8d46d366767b8b40f5f76fcbe679bd232927767387c260de8b7d2f' 
  AND token = 'kGPOImAoH+QCzQMSP1682jen2IgK9hiDdFsCAbnoqmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}