SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf0fceae6881c4ec8b08f9635ac56991c06b0e1569e2e3fb55f17918317693b7' 
  AND token = '9V+Ze4AMCJvylkJKGIQKGVBI9dhHFhHMgJXpW73lAi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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