SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5de045999a0d59315860e5fe6f2e031fb20c610656147d0de12e1f0ee2a87306' 
  AND token = 'gMuD0wENtOcbw5bVR8qTKTNvccGVDE7mFGQlZzBm2sU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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