SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '215d715a706e148a949e37cf659fdb82cf2db723a4ef269470b21739ff140f54' 
  AND token = 'xGWwCoLu16b7QhbGi4m2534kfH118kxNh2w8hYxqVPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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