SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fefc39575696dccdfb9b6733d456c6797678dd878094a4d66436f9d4fb26825a' 
  AND token = 'oO137TM+Q7pS+NEDeLZNvV1GjW5UFuy6npK/H8N49zI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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