SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '744f2031a69ffef17351bdd83edb07010814121f65d9f5006c1799438702fab9' 
  AND token = 'HrzNfOwl7Oicx2j0OlYRc1kp9u3wfCcJfRSQrpRz1cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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