SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a372414ec8d80d8a423b8293f0cc06edc9d904ad2020be8e1e5ee4788146bdd8' 
  AND token = 'YtnvXV2lP13o3MIzFkzUhYsRkz66vaECRh7+y9bnaTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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