SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcbe9524adf7393a1fd118c525ede1c23725d335c55c4c0961cf076327b3580c' 
  AND token = 'D+5F0Nx5OECVoZMcsCw5KuVCUAF3fi/yLjEtB8+Bdp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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