SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f18186318ffcaee6eedbc13fc420949b91da8dbc45c5c32aa80f2d9b93be811' 
  AND token = 'dBsnprpeJupe8YwuVSCdSCer02zav/8hEvX8e8sF/Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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