SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '908135a59348d90f8f760a178819435c5d491498f32b3bae42d07af78a6a3597' 
  AND token = 'svfBzU+jm/NIjyull/YFCK11fvxli9Dx7/LryG7sTJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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