SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dc393c70b345e95190af765716541fa813e69b223c99cd9498475f10ba70872' 
  AND token = 'U/vBNDbNb0UQiqEgEitnpxPUCgx3+kjZ8oScmVnQYgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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