SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3b1b58871260b765d0ae4976961861b33a25fd7966829af891fb6bb7743ac15' 
  AND token = '1LhbjEKPr1vOg+m3hFfzqQrmlqKX8a/cJM0QMV9hObQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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