SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49545914580d05cf33947de6ff680fdb57f4f6108f2fec7dc0a6e60702a041c8' 
  AND token = 'E+98jfNj2MvEbmuHSGJDfDStb9TFDsdOjy7YV0PKzuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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