SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd49f8763bc1632dd6d2765516e7fa41aa7f5142ebb90bb205b603e9c76c8abc' 
  AND token = 'eSPZFh1L2UNstulvgS+V+tPthhyniOZ+U57VvVqj2zI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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