SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a8f075484fb21e458b6779ab46239f9b2a450dcce731390030f37bee4536487' 
  AND token = 'lrxNYyRDlBYYeJXtEe8099TWhGWUPCNGdtR791dlouU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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