SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd3d08ac41e84394f31a2296cfc3e1c12338df6991003140b8d13b4e4859d3f4' 
  AND token = 'lWXxfQ7pYzGWRiN+eURkFeCfWaKjxazYSqJKNIwTNmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}