SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85c00133945981027e2a8598dc4e7d63055adcc18c488904da03ead709a7633b' 
  AND token = 'uPyLqlY6lhFN2qCc8MNpyNUu6zw0cyrGbYzKy+dlW2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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