SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a52206bb31adbf754c31eba6065366f01c2e43b978dba8981130147cdd6cb25' 
  AND token = 'z6vbbYMApy7WKr7Z9fhNAakFrMK4fJ97DkjjhKPUXuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}