SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '706d7ee39481803e96b66340069eb61f8714ed1963460a5cb23f9a010107c452' 
  AND token = 'iVhZvgKmjvvwsCnuBfse5tr9R8suAAyNN6kWWdNyVUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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