SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a714983aa0f50eb7a157db7fbe950995ef171f53da39eeb7d4f35380c0cbb11' 
  AND token = 'zCLY9kXqXwV8bmMyTDhBtq5nOdsL17oDC6BQoAUGtCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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