SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '832ab250860fe8e684fe5c1a83843a077d254280683dc1451833b797192bae77' 
  AND token = 'qzUyZTrAF/p+PD7PjQ0kmsQlMcTioOQ5wg2CIjuAiIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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