SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '920f7df397d596e3d9fc81ac6279612cc854baf894510c9127481fbc440ee4da' 
  AND token = 'qNtKFTKTZown/z/RKzXQzeuzGTIvW8vK+j0UJZDXjS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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