SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778df76951a60a5ede7fc01e65db04ce7247d47ae479603045853f7031f9e875' 
  AND token = 'tZhZAWDi5cMgIyAW0QHt4rrJeVfboLxKTkk+2b5T6fo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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