SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '165bee532b42e0bfa151e355ee009afe43ac52ab657834aaffb53078beb649c4' 
  AND token = 'FRJU8U4amjsJ+EUbnR3nzzXE7vu8bgoFncIHJeGnepU=' 
  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"
    }
  }
}