SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a613551b335174488b7abd1985977fb7a43ba0f2f8123f276d2e2cff514b9b7b' 
  AND token = 'M+7536DeNscCgEcyGpzW/JTkILIo9A2UrrbvAgSDF+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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