SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec015a921634896700e847cb50c1d79bd9fe89412094b725783cd419d8fc3de' 
  AND token = 'otv2LoLORHIEMqIWA7nmqXzT4clLigAwG1YJ4oCbrjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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