SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad017135254f0ec9ef7194ca38adee4f8c0032115473bc2707250abbec515762' 
  AND token = 'OgN6dzZwduDrde1EdFDvchvNt8hYD4KFbPWDWMvl6tM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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