SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf550aefd7710ac1825cdd61e49eb8ae72d4e8cf45a54a275e20981b1f9b625f' 
  AND token = 'rsgkwJs6KcseZWwjNf/fN1d1CChHl4PL2qQu2sAAgZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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