SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e348e284ecf6cd900b59198a40c02e0aa60487653df79f09c3e57bd73f3adfc3' 
  AND token = 'Iwk9qPY6Jz6ikXhIGN39t3AJ+zaWEw/o5jPW0VQhGAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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