SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd84446d192c0b0a6f7824a37399d3762f6a3169d49d60196955c3e6b92fd14a0' 
  AND token = 'UJpamkPyU16Pqb+uTlNU5YmQQHwgzjuP9upafurhJZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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