SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30bdec799a40fb15f5ef8c37e6c959ebc91229df11560ce124896eaccb1a8d96' 
  AND token = 'XdDGd0PeANdd/cDeuYpS71jGj/vAedpLsRqpDYtmJdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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