SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79639078fcc2171ca806a34ecae3cc71ef4a2ceb4e235b5cd05c403fe510d60b' 
  AND token = 'LctLUkTUk2+MhJtCQDxFzy/qkBLI7OXIk8KwzEviUyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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