SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc3600c23f42e41c36e477310e0d92ee2d304cd8e702b9acc2225e42ce376f7' 
  AND token = 'DVRD40UesX1xYaeTUX9Kr3rfcoYqSXoAjQOGwS27lR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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