SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0ab67266b76e71c25ecd45b497bcf84af9588034bfeb60a6ec0f27bbfbb64d8' 
  AND token = 'mCcaR7gD8t7CelF6bI5BjE7Vqzpv777Hy9ZSsUa0Y54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}