SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3671f4bf015d9f9e7c15d4d2a13f775970c93e9323afc6e7b78f3a4db719f616' 
  AND token = 'tM/45IvCR9dYiLzqKAQHVwUigdQC1HizliphLNrJseY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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