SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a9903b1d5aabf3867ac6d3fcccb83af9f35b5f1d8167f054cbd7fd29c068c5d' 
  AND token = 'kSyrbsg88/PT5NzviZI/2hyrH17jlN/xw+MT9fLMaWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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