SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a9e89e96dfffedd246816ba52b9a58235f42db381deae7112d048aa4ee699a1' 
  AND token = 'fzNSCerfvm8sHn4aWH2n5lePi8ZhxzIHA3z0/eRIRiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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