SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9187549190df8e4335c4926c4cc70e82da686d52bcb81cbd3fb829254a461bf3' 
  AND token = '5tu+zKvU4SOQruxzoby3FgVtL/ehkofgzQWYxauaq+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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