SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93a6e20b41b125555364eb6339087075a8a04e711928c1a83266df3b06b8eeac' 
  AND token = 'zlYQtw/Dt1cYrmajCpITUQVcqrBRCoUuz7LTDcgoHvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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