SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d48d5770c515020450cefa77c4f4b0118f5caea839ccdfefd00afbe0225cba7' 
  AND token = 'g9iNDpUzGcLppB2umaXjw4cDUa+up40dqBwqO/T8tcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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