SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9312810b2eb3038bbb33dc2e4d7bdd1e05c2049119b11ec44828e82de7935b' 
  AND token = 'lZ7Itp7JduEOiRUkGp6jzCtH1242adyxpMjKi+PDrGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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