SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f86c47c67a723bb4c4f59d50177f74343fd6f2879755ed31006856042cb72ff3' 
  AND token = 'FAECXqJga6E5UJzZwU81mQWRyZpAaxj2MC/oII24gNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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