SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29d03550e11b9d01f2a7c74d7903f2feda3d2ad0b18a04362365b08fdf3446f8' 
  AND token = 'LlqclPAqYDbiJGhbgUZljO8F1EVjUOX9xFC0MTZ754Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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