SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c341e65b89eac7468eb19b158f68622b299819285ec9a253780729d4f19deb41' 
  AND token = 'qqUykn5Cr+CoaUBM5Xnq9W0BGyHYVvpHBkdEyw0Pr9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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