SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db76195f7c579b36dc7dd3b5759054f428834f25176ae664a6cc7b5af93a3e80' 
  AND token = 'LvmQ/Ly+i+2wzylvedJQnwjgoxwQ7J8IjJMyFtyTcAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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