SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30371de16d73e908714c451171132e5c78e422ef439d94447e89ab144754895d' 
  AND token = 'fLrPJl4MTNN32GKdnadNGnorkeLPg4VsaKtvtPDCp+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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