SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '015412cc8cc67edc97bb7e1a072d58777a4c6ed69913762a5f3db13400c7fd48' 
  AND token = 'Ig+30g5oDX4RDWuCJBsEmkN7sJCRMjVjGNLNXckpEAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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