SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5f44c2f9af7b90519bc450177646834df1755c6652e56113d66579179da0c60' 
  AND token = '/WH3x6qtIX9Zy3/GlD4XnIhq3sKrVNG+IYw8alJiSyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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