SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddb1d3928e7e12341f0c6438e62fe8d6a36549bfb723ad69337f3e6050250c18' 
  AND token = '6Y0PrBGCM9MLqT+WIAJBiyBTUhNxlGD7DUvsLgRzwFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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