SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7da1833f023c35c5b69052ea270cfebd93726240f990304a7af1b758fa0db7df' 
  AND token = 'TXGXVqTcBxSBQEVs66zciQz2hg726AB3YJhi5jGcoko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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