SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0997b8ceba9347c85038f0d2d375e8f1caf4e505af918e427c6558c31f9b3ac' 
  AND token = '/IG89Syn0VwQm8Eg4HpHTdbBbnXJRuQx4IZxTVlicnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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