SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd53b8108ea3b7daa07a076cced2c43659381c0bee26ea93c871b91959a55a8b' 
  AND token = '1QAzQYmFvaf/B4IUmxV45g0bfEGn+PjDeK8YPUq/UQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}