SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a49f3cc7005089106fe74dcc3147f64f6ee566e9a74a34380454084267e8d3d' 
  AND token = '+n6mPhuHmyWCFuBvDWsVmK3dA/+YEpJeLyMaHKuKlYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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