SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdfcc0f737f98f280dbd15c902a0ec861b2e50fd9a9375a475bf0e05b4d92dbb' 
  AND token = 'ENMNzZUFiJM7WSus1sDwv4sWvaz6wZejjwuonjoWCRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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