SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2008497f40e989e84dffbe9becf3018bb7e3afac737f2a017a6480becd3b9046' 
  AND token = 'EFhqZs8TXGPXnNBNbfI4W//b8Gmjficq6owAFw8LTlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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