SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '448fe890aef400260e6885167322da1f0b352dd86c9ca4f1078dd1930e89caf1' 
  AND token = 'YXEzgJqdm93BAgfHkzZNRjzjs5cnpbw1YCkbSEKISk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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