SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '80bbe6df1c68420131595794bb46e760639f98a177e024ab4fa3a2a89e54057e' 
  AND token = 'vrPuos9D//BAV6SCHycZb0kb+3Zx5iiSHWPbcaKJLhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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