SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e2cd083f3aa035106673e59355efdcec118c12930bc4c469c324644a08f833' 
  AND token = 'tmvjqLqLMYrT8tF/SGKXpOb3oNOuygyt7nLwQdaFDvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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