SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5caf300f10fd3e11a56ba35417e773f160646c49f2154a791aab239cd87f042f' 
  AND token = 'NcfSCh5Nr6CBu7V85KnEdmtYobckvOs6Ce21NLtcRuQ=' 
  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"
    }
  }
}