SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3f3e7635d558f2e437d3404de816b733d2eba596f6885ca1a325f32d24551b4' 
  AND token = 'gEVjjCb0NzB8sOxMGQdPAQmQwZSBix33IYijDk0+cbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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