SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '271fe2848e9ede8985f535294b9bb2174ac3d5540512be2cc39b04e69fa81edd' 
  AND token = 'lRVIERTZELc/qJjWmgz/uVpkuX5OzLi24gR4UMmGnWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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