SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f93e84d3f2e4b126af3147643deb690a7a54cd749165d851141bbcc67438c94' 
  AND token = 'gGUDMlUifuXcwRvqUvmsPKpCEmzx6hYZhLZXHyAcRf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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