SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ac8cf5a85e5e1039821a4c4458356b4ba282e23bfd95eba340928e2eabd3a54' 
  AND token = 'UJWnQwtUGvav1rjXbN7xE4DVy4wH72e5V8JmQ2kghbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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