SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ec2c5a5f1499211e660573b0868bf92ba75ffe81ac59e648415bb764b6f64c3' 
  AND token = 'Fjby+IZyHo5AMs8ruoExqljyqQYHkrlRapoZ27xXdxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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