SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cba7671175384ed9ed448a7cdceabf5563410a51e9bb72fef8fb7e2b8466da2' 
  AND token = 'I20taSdGauLucKBL++MqsbloKzMiEzHzPJD5UUBdouc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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