SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e3fa5f9cffcba1410e7405bb4667f399a236ca17a525342554d4d30344687da' 
  AND token = '8mMO8YERyE2rZiuXYOTBzTZiSkpyZXqr1V0BVfwpfIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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