SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a579ababeb9ca65b0dff768138ebc06fc3dfc179ed97ce39449ddd9ff10ec2c4' 
  AND token = 'sGa1aaWc/lOALCz3G7mQeIE/EbXHBGUsETJlwuv+fpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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