SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7a3d85e60d9418d969c3a7c5b9da905e8774039f3855a352e27144244ef691bc' 
  AND token = 'fSBY5HpLgiT+HUWxv/WLyn+Gq4z2re1YWQ9p2KFLCwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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