SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '534f79ee115b850312655cb1b22083b6a4f7bd49e316fdb86bc84d4b63794a67' 
  AND token = 'Grm5i28Hq+6auBvFsB+udgZ9yMIzYceT6uNEvYLg4f0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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