SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69bcf1a76d1d1854be4d73797bd550efbe82b224739887d21e1afc3500e83014' 
  AND token = 'Atgy6Y3bclyrVj7p8c9rpc3eazieYq1p+/uUux432p0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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