SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3691891c1e57c0bee5aa6139479fe8ba80944cdb6918827661071759f77bc2da' 
  AND token = 'KJswZTuLYX9YaUmebFjRaX/603fbZpLuS8XflFS5vYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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