SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff6366b2263bc46bed3214be3392751762134b0ec6bc6f56b6ad4e2655e9e8b' 
  AND token = 'qV+xtywnxENhyKcvdTaSW3gPQkHH+cwsckzGskvLBsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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