SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48f43799e47835e4393bb5386749aadf9cd704c4dd9caead1103eab51940f972' 
  AND token = 'Xmn/QhYeNXPi3U+7ZRWlHF9AgKHcizzGhYYwdEX9Evc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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