SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58e1ddde0205091d0e37713f3fd6454ee352766846a42584f21b23975ecaa0a2' 
  AND token = 'PqO+k0fCzJ//CjEUbdL4hkiEdQ9HNB/rUwhlAG993Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}