SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '472d023b61e880bb9017e15e23dabf42a37c384e93155a5653eae20f40bc7bbf' 
  AND token = '5Q8b+IAYWplHLloMVHLaFRvLG406BqdpLhkf1QGZwUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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