SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c917b9e9e87cae64aa284f1a8c73505d20feccb3ce487bd67b3f1a67cd75100' 
  AND token = '1KL7WiyVpQoRwd1hHeKD181iBDzxxbNzaAtKyKjWczE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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