SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '990ceb18d95bebe713b97d27819f792f5e4fea5a749d2a14f20ac882337c75cd' 
  AND token = 'YslN1UX4Z0hBfxvrFJfxhkdPq5c1e5jinQrFEu01dxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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