SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0831aa8a3a84790e75dd1a11fb3e73ceff56b91f8a5a900bd30378048082b857' 
  AND token = 'YWH2MbtqUe0+DuN0v/GkUuuTKj5BU+j2rqbNu2OiNZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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