SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7948f7d471e804aaa16fae47277936c0d2366cbb18de68262f6c708618446f4' 
  AND token = 'k3mwEEhD2UCzoIVm40LADecmBcTlYmZ5UtZNZQXRr/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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