SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '705e5ea53d1df4b1ba301c52214b09a3aee65c0761425c0ef181a5d315135c35' 
  AND token = 'Bg/uy6ZXm4dKct/kJqV+WTf0zuj5Gi0koUn78CLCn8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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