SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f386f6026f7d23cbf00e67dc7bc712095c540f7a8b85fa2e8d3461d5d6e8482' 
  AND token = 'PH+ckUe//gxxLd0AjKDV8wQGil0pB3XiVqRtqrknDv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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