SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f52382f5f9e5f068a3760dcc5b39264983408edd872651eef295dea7385a4e25' 
  AND token = 'B7tm+JZUfFlzxsk4NcAPoZXSDhFlLIWmFXmzE7MElkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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