SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '028ebc7ca6318cbe16447b522c76fde714531cfd1957d9765acd198a68803cc2' 
  AND token = '9GT+Sg8B5taWysVIg+7iZyvs4QsmFUtkL5OwT9EhuT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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