SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9a9fb851295b30bbf74c84b91f2ba3db1f321c464049b5db35aa0208792de15' 
  AND token = 'T+NGdY9d7P9uuc80pVuSNeKsoZFK1pyKoaa/9BSxwUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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