SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b9e2aa41aa61680f266e0d047875f22aa359d063413ec8ba5093142c06078db' 
  AND token = '/ViikV215hIoBUqbWkYzzzRRsMaz+XaQAxd1NVgfoJU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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