SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '114b28c34d094eb3a93d89bcad4749683745fc4b53f5941d8f3d486295661c90' 
  AND token = 'bH7bRIxKo/T2GI7Y/w6wv1cUA8JeRuQLZVoVXnQoBSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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