SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae6e35fff226f05a6ce8485a75bcf806c5122352cd2eb1632efcec095f6e5e94' 
  AND token = 'moZ+RBwOKhPR6hsBsRCqARFlS96KUTqxz85o0sQvVys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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