SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52cbcb0a0264346a9fabc3d83a5bb9aeaa4fa9284b485b8a15dd3ce1ef7a7240' 
  AND token = 'iMCVqGJ3oKUKAnMICAtu7NAoQPIFWizK2qSjwXAg30M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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