SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '123cad1768b1743c0796ad5bcb630215b8e2cce4643b1e2ad8d08757e56f3aec' 
  AND token = 'iwcn63sgiS526cKAQyioVO9GeOq8ClLKrvD/NwjybrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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