SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '447554c79ea61671334fb10fce4b7687f0d5f50ac3fb643d522328aad1901718' 
  AND token = 'YVjP4ZDXrSC8qu+dStWXvmD2jinQjWaiPpZzOk/zqwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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