SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc8ecefe025ec9264b7169692bab465b873bdbefda28f704365d64009ea73a09' 
  AND token = 'CFzCsHQZatdAnqJsvIqjlxBYwSKD4KKgOHCe/7twxpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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