SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67ab2f20f29b12e174a52a43060d7dff649374e33df25c24aeae595596cbd8b7' 
  AND token = '2GcOzkWB3KxQO76vIkq2PY9CtepfqLGVTX5Z/qCjG38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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