SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '418a75a00ecdaf5394f9fabd3bff6eb6648a5f1aeb8da63d643d5a6976942400' 
  AND token = 'QLDrz+246FK9s+mItWHEsOBDw/L8CalZj/NyBBvpbRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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