SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9d1f465bef6dc1bf582e1abadec20a2d5222d93dcfb6e76241c00111627c378' 
  AND token = 'vszgBTQGIf86w3k716zEt8s1LCtUDuNkeiJPOu7Sa2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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