SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76aa668b8a98d5bb493a5e69d79281cb17db5b6df1e9b60574d5b3bc1f519d65' 
  AND token = 'ZbWw55m/CNlDZmbAXbr+4K5v6tHUayJm+O0YD53VYuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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