SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2de98ba937f80cb109f2216bf93702b41f737eec0e7095b8754a2dd4992eced1' 
  AND token = 'pp59ONdJB3mWG7o/ztuFVcGrJT+5y+Zlkf5p+vPYh3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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