SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8b86a43b2f9d7d0684d2d0395c80ed5fcc8d15c7206369b2514574ac6cc8dee' 
  AND token = 'ZZWMdq4a+ld7g3pL9NOWjiqOgnahCRvudymFgzWd3nE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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