SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '75a6b2e860c318cf452f3a102244faf37ac90fb01340c3b97fcfa1c5675f1c32' 
  AND token = 'EzyDyWduoFqsHGlZhOxOH/B5CrKNphA0cSiAjUEt+Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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