SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '395accbd31fffc5357c96d2d672f3b3e2b2b647c93871e4e6001194743c263ba' 
  AND token = '3CklIANZBpYnf6DwLPUTLzg1ysa2Z+7gDJ/sIMQdJkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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