SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e9b4a60fe38419070b39fcdbd6f3b850355e8f9eb5a8b75dadaa960b4f70bc9' 
  AND token = 'v+cyWO9eRkkGYwHEHpowJoZMq+fqTN1ojo/o95kovyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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