SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57145255ac09435768f9a0615b3990969bab7a22d8a6cc8a5b3d8eed8c2d100f' 
  AND token = '2mu9VkhJg1h/7nQVMMqo1TnK+wxGQ4EtVbXnHSMShhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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