SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90fd6f4a3eaa39ac72d93887164063186d32498bcb21bf516cb94465141f4bd9' 
  AND token = '/TMgLserqO7YmqkJNNU5PgT0fXIQKZt5qOiYZBtBxhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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