SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b1a3714d2451c689fad8817a764578d9d5df0fc1636e855f0ba2c6d871efd5c' 
  AND token = 'YhuzD071bg/U86yN9FxvpY5mn3eCVpJglvLyXL7XZiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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