SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '9793deed1fbe97a8d7aa9c7f872a87b2ea5a311233edfb412fa307b4b2094293' 
  AND token = 'Rud4KEjiXxSrjHK+gp7yephxChwaZ/nGbiLGk6Tkcv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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