SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d91e70cbe46c3b4dca5b3f4c9c249dc7e278e785ffa34808d8a986f4ad9e0f0' 
  AND token = 'Z2uIvt4OVX649egqKk3XAcipg1/H3Z9d9eTkexRIjHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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