SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '57c310c51a8353080b722d9e5e5109907d2e001da37f14bb5643b02ffcc3e2dc' 
  AND token = 'RgPwQFn0ik60L7BI6zHryCK9MAVzMazm70bI+vpLiAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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