SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e6dd971796e5b9363dabcd8f0406ef7a11ca94f98803861d574ecbbd0740e31' 
  AND token = '3dHNbype+0JbirpFwYTQv1TsHzMc7vFfNUE2UIy3yww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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