SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0518cf7808503d6608514873ab0a4f56fb98ab4eea048aebe327fb9eb8748a9' 
  AND token = 'l0T0U9/a7nLPdtn3ry0P9QQLUACVUgypt5z0VaT6JtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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