SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd4b276bfc17908a4f1b063631a9b458f3937fe38510e6194af85795b16a300c3' 
  AND token = 'MfQTH6sQUwWxS24LNYrypKiBX0kY1a2PVS8Z2qAumiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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