SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39a81ac1e414fcc0ea4363bc55ebd66998a94d7be1ca4baecb25dc7d146b1727' 
  AND token = 'dPJ6DwFUtSqibsEd8ZeXE9Eq2MhzBz6f3W72ofF+Vxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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