SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef77a4db73dc28f964a29b072dba64f97cd8d73b7e9f0e4e0cbe9b63580bc46' 
  AND token = '8iitUnvJQvg1wszzrK4njSYqZA5/ZqWI6GIvBNO+RVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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