SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '63daf1c532165d42fb99200d8b4a975f7c80563fedf1ddfe300ed06887ddc206' 
  AND token = 'lzb0GOkGTsJipwZJCL3GMpqPt4Gkar8ufi9PLRHU7iQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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