SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ef49493fe36e0fa55cc02417be7c5cc681fe77d83f0474cb9353fb44a043e2d' 
  AND token = 'JkwJhMBVE3C6J+K2yUda7rhmfj8eGjGv9Hq85DUc/Oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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