SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aae180137dff235eeecadb9d9f2d852cac142363da65819758be3cdf34edf2f' 
  AND token = 'qu1D6yk2TvqCwGcHP/yEYdb++vKSlBCYXHGM1IOdDpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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