SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e103a56bc7df111a02556ec247d232341c8e62264ae7d9b5778315e9bcb6f4e' 
  AND token = 'omoBglB3hibwrjFhcdXnyAUentlHlWmjvzqtzWORqMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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