SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fa631cee9316a2b2f4a405dd3540f4d20be4a5cac6f55379f7548b302a2cad9' 
  AND token = '/0GwHmr7KBIeWoi7wjuWV7TU7UTcZguGYsYrtpjVpdI=' 
  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"
    }
  }
}