SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8b9a0c8190a2691f1ade907bc245a8658f20dfa1ab842113b4f8c3a1e37fd54' 
  AND token = 'xhoi8QqVMHJrZSQ0feVzFZLObWHsMq1brNJx4PFNqGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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