SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d9a37931b58532d8543ac0163c7e5794f8ddbd325d35fbac8f97d388141a4b4' 
  AND token = 'd90r2w3b98necXUJ23suTtDuW36U+Kq048LQn+AApqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}