SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fb5af46311941136656b674c5eb2430a3b99cee9608476fd797612d85ac9da6' 
  AND token = 'WtaxzmVmnKyn6gT4M8UnhScG/FWHUINUyAXdV/SHGz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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