SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c825ca577e48b6dd4d996a32fdad981bdbf3a2001f18773261d2af5cc0e4ff68' 
  AND token = 'ols1DdthcESKs46QOUw8ZbhNEm5wde6mZN3FnOxHabY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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