SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ed5486f06b6439b578a410b1297edacda62520206af5bf3baf5256b2bcad15' 
  AND token = 'sVxHqfjCRqaNa34j6QEZpaVRbkeoW2s5QZArqmPblzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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