SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d0899a94d02e3e714c73378737196f666c30f83af433868503c27d5f11a6578' 
  AND token = 'ktq+JqV8MjRpWWcaFhPUhFL2Udlg2CoMZQYvwnnmd4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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