SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6869f1f2a5246cd84969617dd45b6ee3e932da913b823a8728c7c83ecb073c7' 
  AND token = 'f2i25KoVgq8+BjlXAWeTFZdu/2FxNxSpggAGzKCLN3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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