SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6c7f27af818f9c2cda76257c7a605b4133693f229bdcdee988be586ea43ed13e' 
  AND token = 'vG7Pned3CqK2KtbngMHEQR3QmadgngLSiaDYUVanZ0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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