SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '246d9738f9a7dc37cc1a3a717a95baec31b11d84c2e886716990bd456c46b194' 
  AND token = '/TYRhpVZUAQhYKPv9PnB4RpPlXvFPdkFXGBtzKcl3iI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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