SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efd15ef0054f46d663916e7f940ce13651beb4f31da7904b3d61b43359f19953' 
  AND token = 'HPaaqExK7LQQYk2RQhYyfVjBoK6C4iBwdFdMjI3idSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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