SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e30ade1c65434c4b9aff0703f3fe7aaafda29a1f86f10bbfc24eb9fd3ec359b' 
  AND token = 'cxdF6q7kMjKkz0udohZW+rxgsaf5VBOKX2TgnQLvJjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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