SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38db859f899fc89d24b9741fdd98ee818a72e0aab93fe8b57cc044dce4827563' 
  AND token = 'E/sMVtDXY5KMhJHoQMvfIBzLj+WHKXwSyfVDyjmqyPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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