SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b6bdbc26dc70fd18d4ed53706c453c27ebd2f108cd858bcbea7396eee5e0f0d' 
  AND token = 'kkPIHf4W1R9dMC/YovswG7PZdpFVQE0BnYGKajEJikI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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