SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5bc549735dc780458c92f08eac8951bad9cdc6b463b8e1715faa65604ad27f7' 
  AND token = '/Y5oXNcVyKauLzciLpDvU2PAYjavFf2S3qOqe3es0ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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