SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bc26e699dbe5ebb73983162c1f824920d900a79f25af4dbf97c287d1210bf0dd' 
  AND token = 'fJiHYmekzn+0o+0UOruYNXnDE33GE32NPGkLvEzFRnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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