SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fcf32df526a2995cc1deb1434bf72288effc207df785e2dd774eb39ff003eb7d' 
  AND token = 'VuuXOcwX6/ej16UdXpND0Hd6x1Klo1diDCNlII2jfQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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