SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f821f094a1d150584d1d04b6c9557aba9706339b470722c6fe4947f261d0b50' 
  AND token = 'CHfDEAFSrNqv9XQfaKeDP+QRfUZgWrsuPJ9Mw5ll7bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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