SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91f9853311cf7eb0e412ac5cf72806768973d68ae200908264d42a5cb379be24' 
  AND token = 'ESpsXbbqHok4pNWuqF2nZmo08cKGoSd3+XuZvIJc4hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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