SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41f0b28b796b708263dfde82851b344345bedbb2b6c6dc7258d36d7a9f31a60d' 
  AND token = 'RMtAbWphHiPmXl/9Ci1AgcYU2RxJfKzdeFZIpn4/t3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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