SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5aa154442a42463021e61ef2713db3fc6cada556d0eeb16c95ac10626b19369' 
  AND token = 'qK8kA9TvDdezQYG3qsikCXfGl9dAgJzqXAJdEBYo9QQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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