SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '635a829ca0990b833d81a6f21e68ef158065600fea2b02e9198426bd277c387f' 
  AND token = 'RlhwpUuDvOEepaUjv8k2dnbjPHy2yIOAGByjfzeKoEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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