SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '758928db1309a8fc338aa2e2cb5220dfd3e9355142f7c9821610ad4b8e532499' 
  AND token = 'GV4oQYdhCfmJIEPg+dnIerDbbe6eCtgN5j+lNEFj4Jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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