SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0121d542d3bfc31562de06c0a6424b3a7c9fd3372bb43185d685c297e31f9d37' 
  AND token = 'GDqZjk7e/ACp/+TrI2K4+vrPXofx4vHXgR58UnJhwW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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