SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5324b843786c0c8e3d6f2f1c615faf124f42af953f78d99659562fdfd4ad1ea' 
  AND token = 'F9MRUTgA0wXjWj7AkHTXoz9TjfGhiF9M1KfDGacE4kY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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