SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15edf89aacc1036777b64d43495511db3719e5356728eadf6d51ad8c44639d6f' 
  AND token = 'NkZaWQlGlTedlNztLPnO2nBwdxEasgbp3glD0KydMz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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