SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '317140f3918c61987cd8e2946820d5d6c40c05f8d9f77de25826bd202653e4a4' 
  AND token = 'YpBIpFbYYOhE/rYGDDUslobLk4e5wjXvQaye99UUKxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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