SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41594028545cbabc32d7c6362dd78e70abc995557ced1148376e1781e248f7f4' 
  AND token = 'mLpgkz+Febt75UTNovJKgMzPfQwqtwjg4iPepB3XE7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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