SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bbf5b8f4c323d4f258c7c348bf9eb83cc823803f8e193226e4298bbfc4154a18' 
  AND token = '/DvQ+mldGrUyiEvFq3/fbhjGq7ZzrAQxg4vnM49Qetw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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