SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '777d3def31e4536c61340b85ef61f548955807274a4b8d0ffd971f33e421255f' 
  AND token = 'HxWE5sdJ/zB8JnFaJuPLjfD+gv7ZHzwLR0PmnAOjP+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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