SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd4fb531e284d8aa82e19026c70d5465e4f72e1f0398134f5531b8fb417bc6c9' 
  AND token = 'ATKwlyeqGCKo1/XPrhgHTJeWwPYC6nW0sAsImiHhAEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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