SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dbc0c88c57a57aa92bf7d099436216fe4f4f9111ca43a0015ccfe67db824b53' 
  AND token = 'ofX7yr2XUamTyn0UjqDjtJtT9XljAiKsNhvC/weTsyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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