SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17ce8dc05634f9809fadcfdf99efd1a9338a621e2eb076fc9460977161409f17' 
  AND token = 'xnXfAje7yJVEVUTjqsBalkhUgPwfM1RJmVIxyQJEZM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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