SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd242b6461ef4561528edb2a9fdae9a1487205e7935394a19933b37fe1c40fa60' 
  AND token = 'jbBRYa8ftDUzXOBPK8sEKTvkDDFgwoZLQnIUBtr2gss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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