SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f572b4f1fe1f3b52831b95796bbd58966ffca96a265a30660c3663252c910b5e' 
  AND token = 'z/wjR+PmYRUjeCnIpIyPKSO/4JlexiNrLMYwgXdhUhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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