SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b9847b4eae7f91250e654eb1c23c1116362dadb30c36471426ffcbfeab047068' 
  AND token = 'apeMz6ex6zkAxoErrMYK+eZKGZbVvJ0mwgDkxUNfFww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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