SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28796e2d5c8025f22ed15b819fee940bad939a0ac12f182db47f92de91df2b2' 
  AND token = 'eK5OqKycDe9jwu0sZtxWEtj57p/yjdxIqZNAluI+pCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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