SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ab052d8e412e0c3d91e57933c063d8660da9af69f98faf0a08fa51a475a3d9' 
  AND token = '3hfNqkbW5ApyyAu2Z1ohkVLsvNtKZ4DH8yMYmJdCsGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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