SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea99f08449d34b6dfa76e809699bfe774406183a7301ae6070f06ee52fae2451' 
  AND token = 'f0W2ZFUkUnKYNdLIxUxBBKXfPo+KFvVEuhUkk3C77oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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