SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '947e96614b323b8cdeace9d6e24869ef5ca7b13ce2405e9643074e7b95af53f3' 
  AND token = 'oa4XFgEWJRLyAhXY+GmB/qeUkLySvKkxAQqQ0uNMTaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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