SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e622f2103f09e8e2034358b85e8f681aefa0a64e68807c5266c73160019d96f' 
  AND token = '1EvWgRu1PVovqdG/dh8FQDfP0dLQLlwUmlxfU6QQ9V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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