SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df39771ff3ed95d93335df03da9aa7832a5c540d9f2ba6cf59c0b71871fcc871' 
  AND token = 'VTz/yfX70nrMnY6EC60aAt4B2VDdgHL3EIhEkPsenDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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