SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2d37091a95ff250ecff4cd4d13af7a0252e5418a4e1693b5a94a9827c6bf48' 
  AND token = 'bujE+IKGz731U60Ow2WI1FN/n48MTPsFH2iRpgToZJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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