SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7654570df66a81a4bc42a70f5a99ab1fab83d009eb8c3f036eb255ae53268900' 
  AND token = '7JyRVW8OrOGtZ7gbq8ZGgFtnzHkFbLcTSq5wodbty1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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