SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3f0fcb4f433a448c82413ec4b4cc5d14d0bd3c970e2b24238af0030aaf3d8448' 
  AND token = '/gGKkIwDCE1xT5O9p35Ko3xJNxUp2hlK25b0XA7iTmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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