SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fd5af557e7f265073ed3573cd187a3bc7805c79047554f1f74e6fc5b926ce817' 
  AND token = '+Mfl+YUmu6nO1pqrZz5x13/1E+yMdmn1wXdnSaKQkqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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