SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd77282431f8d65c063fbe692956abfb4a09cc5b0c90b58a359d442fd5b8ee8ab' 
  AND token = 'psDqD0tB++xuDdMYKzA0LWVSZS7YwZ78ZvWxDh4Tw+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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