SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '350b3f288cee2df989b894dd5af52361f3b36640d3374ca3044d73a189f7d0ef' 
  AND token = 'cn/j/J5igxBIKnzbdeoYtIxrvWNpvivAV/7LhJBi030=' 
  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"
    }
  }
}