SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b48bcac94cbc4ff019a7e4788d53d8ffbac96d002189ea22c52a5941fea32cb2' 
  AND token = 'ktvzHQg3mD29y5lzPwrJoyW4tHvjPzFYRVVKRjZMTNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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