SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8c121dd06ba3752a2d765e1fa2822d78cfc519efe1bfd687cd5f86359e871d' 
  AND token = '1ZJyclsk3o3TTjhMStM0pl4ZuU4aKCx0zEHW9O+IXyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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