SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b1dff93cc6f3f6265849e488e104e269afe345b035734b340094b69b66dd96c' 
  AND token = 'QryuHF71FLySngDKCeoM7hgEkCSok+0NNlurDKvEDnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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