SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '56ee3ca712dd411574ba616edfe8bfc6b777646465e3d8a587014f5b743acb0e' 
  AND token = 'Im69pWPoLIFRn2PMEeC9b5bOmYt37Qq5KWR00LG0Plk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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