SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caf8acd3f8069eb747a11bbddfbea41552916ee3a00c8209623bfc98462fee49' 
  AND token = '1ZToeLVJCXl2NaGJ0rpQz3Odoi4MCeVAhZj+LPaE7CI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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