SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1323116626f468ce8f69cbe781319ae1f401562c9e8e7f7a4f24fb635bd8e05a' 
  AND token = '+FKRYKLpu+AmMzZedSBXQvkj/yS9JM/SaMNOiigkTzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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