SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6bbe3955bc14060405377aa8777682982bc0f43394662acb663ad84780c679d' 
  AND token = 'EnWc170wXAHiGQMSacm3Mq0QUiYFKApjynvQa2v1pak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}