SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '27999f8dede902c9909f796a0fc38ce820b7e448e4886307531b8f17718f4095' 
  AND token = 'g+OoNavum0dFfExe2hZsWjGdBnlYT6oOiKaHGjuEJ64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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