SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a08df76779519c4965471f874c85212d9dc8627cb88671df1fa8c1558ac9968' 
  AND token = 'ngKTVBGYk/K5noANG5dYKK8iIUNekDEtukUQ/xqWjnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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