SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '30dbcc2ad0ecd68b98cefa3fcffcce41b02b2792404f24cc8a36de814ce076f8' 
  AND token = 'S+qLU5u5/JFsrIZz9btqF8H+khsqbK5vxbtwJBmoYwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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