SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b9f2a3fae57085e9a659fc163654cd382ee9ee77f5f4e2fad4462648d3062de' 
  AND token = 'Nxv7D0w5oeIZzmqrGJTsXKXBCNEvjbrOdMENKupOgKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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