SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d3d0325d6e2d6a4428ec1b2837d569452f7400ba12b4ab4c89517ee8fe3de36' 
  AND token = 'MZiicEjRUHQhZ3h/4bvxsvdWVYeFR6+cVPZgs1tLViU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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