SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96b9c535de540c42c131abfbd4b614454d20f3da343b816f2ea25710361abbe2' 
  AND token = 'XLxA0uVm34xnrZZoHI9lQhx7OTnNZIzzvZIPqUGlZ0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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