SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f259261b4b5d520a23471d1ca5f94a62e707e5a939c4b6170aa33bc978bf77f' 
  AND token = 'KpKqNMUYa1pKRg9BSQX6MnQbeR2mIlmYVM5C1vGdysA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}