SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7be5669b72b54b97acfa661e9dfa86593f6cd976497c278340b93bd547b7255' 
  AND token = 'tVnKVOo3n7jLUkTu/Bv7UocnjqdXs8/s3+U8wjHKXmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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