SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46903ae7f92edb9681121e0a5a20136a38074caf10b16a3b890a9a0ed0409e58' 
  AND token = '2BdGFXD5t1xVgQVHrI7HnHUqCgOe7zyCFpfDut2Qjhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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