SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c88dae1f1405ad6dcf31f49e97127720b846e2c5c1caf0280b91ca797953f5e' 
  AND token = 'nHJb4O2KuBx7ux6yUz8kDvX/3A0jdxLvagqWUfwZ0oI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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