SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fc3c3439b3ae2aac7319e1249aabf9bff24e54935bc2d7550c6325296ce848c' 
  AND token = 'yx4p/pltUi3Ntr5ajKRWs7hMR08bgUz01fckNIVDAvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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