SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '450ef6bf75b36188055bf95d8c1d8b12fed2a0733a19361d25f68b8624370c39' 
  AND token = 'xhZXsPqrj0Rs+EfMdAZzoQXATUEPsDQqKn0a3ovEClw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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