SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c4927ca691aeeb86bdf49531fa5fdcafd880da22f98eece346858027ec9b50e' 
  AND token = 'aJBeKRrzZkRkZkumbI40kDjUa7Ykzy/JPv/P7VXU+0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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