SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f3fd457f8c24ca408809b48c56226a9018973a98faa63d78d360abbbe78ca5e' 
  AND token = 'TLsMbzgFYBBnTLq5FlleULOeCwszm7DjVWmwFmy/L1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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