SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '252ad90dee1a85b54e7afc6e11b67bd47a3dc54a50883e2b23512872c11f4b38' 
  AND token = 'WBOtG8OflGpJvp/HPrQuLlhgYe8QjXOhRjsJn7FunWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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