SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e9b9cebc6b5280ac6e595751c9084f518e07230711173eab8d76843885134df' 
  AND token = 'mlhpXaEwZ/vqSDbsW8sUWDtnnnl8XH63pY4tcUoGdTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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