SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16030900204061cb783c59725a2fbd74548e50960edd06a4f283a0f52992bb36' 
  AND token = 'Hpue5Ri57wpigEVhn/tKdwmoP5RnsTL5IZf4fiy9WNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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