SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91693497f873a6c3212b3a570c710f93ebefaaf95bf1f94af504be3c2a64246d' 
  AND token = 'z7mg+O1VTcAKWTUpyJ9h8y7W/DQmvonliUzq6TTnpPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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