SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9649b3a4e7fe9b516a96800c819768c785d77b74a9e29220153123c245f47a52' 
  AND token = 'mJQrwokkCv2gexUS9KlHeSC8/hK8gwY0U3j7Ozsr++8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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