SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19f9e20322bef24e5ab6bf61b58c6d126eaa599bbaa8d24379be3c6a32bc0b9a' 
  AND token = '6SqcbOFBAbieYNK8PnhqnfOAeBydOEBBlsSNQbrlndI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}