SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '335afc1158b6022d4008a8ceb59393868b25d511fd1240f7a1b0c29b6613418a' 
  AND token = 'lKroJMvXz+THARVgkZgYFyXs4TLM/EglM126BwTBFqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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