SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484d200691ea9c35bd791f7fcf11c20387e2f5e4a5921ebc2be5dcf0b4ada238' 
  AND token = 'WfU3HwHdt8PlddHgfLK/LNZjiRcg8Z7lmlCQVrytjyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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