SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fcc2154c1f17fff9a6015a09169d26b7253deebd90531498942d751fa4d0c01b' 
  AND token = 'OrpfsyxACpdSVm3RgmJG8Szzbp5XebpsBAdqNANrC30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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