SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '613da9f1b3154387db5f37a26174a590582dc2217912a5b9456f2e69d892fe2b' 
  AND token = 'YToMeQeY9Q8kASMQau+LL43J+7dpDWlZKfDCGg+wlXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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