SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cac765372620ec2baad965239a86c3e296a982cd00f382b97ca764b3c31840a' 
  AND token = 'r6fLoIf5SZqX0iNADs4UYNd1hJgBmmlAI4KvV+jiGGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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