SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85243835793b3b5f7b62b1487a89b878df9c8a251566972dbe2188d774dc006e' 
  AND token = 'VqHTwLli96ehqocbyfbnEVN1yYPTjkbgk+PgVL/PHzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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