SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '585df8d29edd4f546992ea42a8cd5f3ff084d522d44f6704b59594524b5169b8' 
  AND token = '2QqHlPDJbn/WZ8339zLP5VBHZBVIk+ieRt9o3FmjNxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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