SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81eddb29b0d0554ece295b6875ce143f393f6f78feba3db6973e0981806d9085' 
  AND token = 'aQZ/2d3d1HXqCUz3TeRtyn34FbjQCODNt7mL2YRUQN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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