SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bf84fedb823f45d6f670f077efe957c0fcc80288f304e366d9b17b5b97cb527' 
  AND token = 'nVp/zHCN+emheftWVjxrG9vfjhfGmYcNMVQABIj+Z5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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