SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7ef8e3caa402eaa2cddb4820cc2979ae4a0e0f3f12209798651fdaf6dc189f0' 
  AND token = '8S+Su1JwjqV8vSRu0dQHp6nasGmb0BJ0lf9UEJqNweE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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