SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3514bb3a47c04e16a6becb420e5a173888d6dc3ce6247a43221e4bf3e763f5b2' 
  AND token = 'miCY+aw5Jy1eh6Wk3TWLTvWz7Qh/GK8UI/9mVNFlpnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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