SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e64ab123f54456abceb3c57a436dd4a625c28e7209aa79ac3074a28606878e' 
  AND token = '6o9PFFuCSCkNvW+KhN+XZul8/1fGwD+D2cF5WyC5ijk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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