SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5af7c21be26a294deccfc90fe3183b94a4db8602bddc558a831b5c225a4d9b2b' 
  AND token = 'eKDWY6azo6/L96hyaT0uvg1pJOu7bLt8XsqN0MCyTO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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