SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ff0930fb4931149c618ef0c021103a0d6b64b647ff2bd3fc9710dbeb7962737' 
  AND token = 'WZo8kHc/Vvi0yPyxuSgcFn6mjqQmjpLPG0oLivBGpYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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