SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'db62e4a9389fe580bc4b93a0276426245adee84186f2851f533869cd7ca2fc03' 
  AND token = 'AzunPt8ch9FYXA/u9QVmf5sAwOJK9KPeN3PIPjsusnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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