SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3982ebb643025ffdcd3cefdc72b2bd0106ba5f0a61412f908219b38a59e34992' 
  AND token = 'zQEktkyNCKvamI9qrBbofm2qQmdPcNhqghe+024DZFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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