SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d12f9fdf4d9473e764d9d94401cbc6292f88369867c8431862538265a9cabda' 
  AND token = 'ElHIFsqz4jCOGs1Sao/1EOyxY/J7I0vWQKZzeGDuUmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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