SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c8ae63f1e811380f4a71bd385921493efa877584296c70959ef557c7e8f8297' 
  AND token = 'pAkyjeSFw/zdDUsDStGO3HljBBNkUfKykbp8vZbtujU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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