SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '952bdc3554e282a1a103c01e0bf46a42e9244902c3dc5850f4a0218b37f4a4a8' 
  AND token = 'gEmFvhbXITa8q+eGPAu84PLoqjq0oMyIGWVUC3MwVoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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