SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfaec8ebfe5d6e0f3dddd54956d9cc2e6cf7ac002524cf987d0737c372b07be3' 
  AND token = '2xGWXB3u5+CBkpoo/jh8Fui9qAzpu/aCOPJYFxF+K3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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