SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c865869eb1ece6fed6829a4250d1c5b7855ab87b13f03eae0696c7a0d64a0f39' 
  AND token = '2K0qyT/NEnqImB/2EiZnV81lzgxOy8XYTPzTEWHezDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}