SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8fa2b5c551c8ce06325912a356816092b695258428d112125e28630902fb5b3' 
  AND token = 'I49blfEuzGWpoko6zS3HOh7koxvgOtAcmECDzCeBz4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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