SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8eed09518b2acca4eac28b561a89db3f55d192c94075041b504f8b5b9c3cd46' 
  AND token = 'lwuObWTpQKc7RqLHHPVKp9oCnYQufjtjn+F6WNHkIaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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