SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe0e88d86ac13abcbf7895668d6d5d31312e73a4563236f9212058f215926340' 
  AND token = 'FmpKfzE7nESVm7bnexTat7JNhuE/tYp+UGZDSzCBdvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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