SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f16f8cd65dc7d5e032f6a2229438633cefb6a2a96b61d002f22c548ed418e45f' 
  AND token = 'JhEIQvBLf5/Kw8KYSeOTQEkN+7Ph/vWRzEUFKa1SJKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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