SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e962ad31243224aa0c714f9b7e91838c6d35e95d7139721ca5bd3d8cb8b3386' 
  AND token = 'EcgwqdSKA+XbvliOD8L3OzIq4TEtWmQk7pLl7iu3/xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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