SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40478d722718a5fa92ddb83e88b61b9ec0f9738e02e4b7296fa7b220ac69acb7' 
  AND token = 'nD4lvsOinwovVGmYwPhPvbIcMM2oZT+W0tzp6XSBpjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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