SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf538309c0288094e3eaa520532f8ca8986c2cebe2269b14bc25689b47b9a384' 
  AND token = 'UnOuiquXLeuJ6LvX5tPNhkC94BXNMX3anLYKdtMfn6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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