SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '902cd87f7b5b086e2e93b4b52e1931fbd02206ce8df780ab94a950cd47185f43' 
  AND token = 'mWcwIuazPc9GGUwvWqGHBE0JCfApd1JuJTUZKWs93A0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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