SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '749b9b7dfb6768cbc53789b740adf1e261cdfa8ed99a16b5cfaed95a431807a7' 
  AND token = 'GoOcwZJtPZaOhklRAZ0qqL30UiLY7tW8mUY4MMChIA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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