SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '525716347989501032818205e521336bd3352f6a8532b061d3083e48617afcb9' 
  AND token = 'UQVuDsi61J0Pir/afJuogYnnhvY6V388HSAoqKiktt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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