SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f7ae83674a4e11357b38a67ff0f510d4b855293ceb2a99e45bb9a5f17681f53' 
  AND token = 'gTwC6OvM7OyEi4DJEtDCwx5pzEW+jfDSJhjNqmQClXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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