SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a16af4166136337636779e0edb1b35ac5d93441951bcf80bf4568d5f2bf98c36' 
  AND token = 'Zwojx14BT2asxV0QuATs5PJ1HjtHFqrOMchQSrqYGyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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