SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0adfac9c369cc3a3afb5397e52a56e2d23909d5a9347fa5f2da655ef0fd23aee' 
  AND token = '52kWNkkWvbKwgEYsFHgtw/fEyrFJKcTpRrnRItM8SKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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