SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6df3a5530a8d835e9e640272a5ed1301e09c36135d2a4c69245ff58fe4012fe' 
  AND token = 'eLoHKthyv7XFEpzm+r+0AkMONzsZ4QyFmqXSVnFSnDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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