SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '13df29f977409f841be96a2c761596417d2b6beb25caa97df4825d98795c24d3' 
  AND token = 'nEy+M+ngIBSVvhNuI9tzT7Hbx6nerdTkVT3Le50zdrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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