SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e6b3aa989b46e74ab1f28d543a7fd6b5bcf58be8125841212a17cefdcb4f499' 
  AND token = '/+VCiCUdazlAF3JiJa+qQnekVxEeILbMmSEF6IZN+LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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