SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42513d1e529304f77baa9dc397a8b5842b16fe9b8e0fada5b48c4f1b7267b29f' 
  AND token = 'qJreZade0yPgFxyHIESFuYXlfjHz1WSgaHJPwFoYfkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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