SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '711c9e8de42caad8afd613117f6213cd43695ceb7c9745f564afd494f55be3fa' 
  AND token = 'RpgiKS9XMGKihS1pglEyVqW7rXrxoJVp9PE/wk+nfkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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