SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f52b1739659f9ef637ce1d711a4708b0ecd3535b78367302fc51c0419d38999a' 
  AND token = '8bNPVhA5QbmppCogV11vE/HW5qQx8GV2OE/JdtgGQiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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