SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '105621c61723aa8b93d2f215b15a094ef27098b9d1b7664181036c36780a9ac3' 
  AND token = 'rQbO8JsLFUsdpVTtr1lEgZ0QdudQyuT1o6tFi3hDvj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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