SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8bd93964662c020dde1dc26846f5d2a2a3c67609725051150d36c32b85a3e5e' 
  AND token = 'TYu23IvMUE0UhOgK15gqOBCGc6m8mG2q/yKiiYYMuyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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