SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f7a80ae8ec693665f992d487b772557e73f3082d51cb4867ace86755c4d8e4c' 
  AND token = 'hnxKn51pjgOE3JDtcXgr0qiwF8MdUGs8jMWLTxMxxF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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