SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eed6a14f0f32a83665a88da4237a6b476a6867682dcdc33efa355b5e3b237de1' 
  AND token = 'VSYlTp9grZ+bOhuigPo2XYV6GhqY0sZjfOwnoZKLN2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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