SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '056fc0ac7df24ce2e4c9082c14308961cd63c98f16c9695bc7751fc3b1ddeb32' 
  AND token = 'epy+Z+Oict1yAoXZ/L0arfVpOXjBhJaxKGqLBoBKjiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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