SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad316cdb738c549b4dda2129e98c3d65c3ffd078170f6defc99e23a76e0f9761' 
  AND token = 'gpwING0VNhZNcmkBtbsHWHDDEQOfjAreLQonVWeiPuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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