SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7a92d5147c8b26898727bfea2098fcc10317c2112d7c49bc25a6980ee5e66fe' 
  AND token = 'WEgRAew2omAw3H0kiD4AVudBzvL6B7/6WzgtNl2pSKM=' 
  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"
    }
  }
}