SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de9c3905193688d5317a7a14ebd59bc23ed25c882ade7bb70ba837b0272cfef0' 
  AND token = '5S/mfrSxfMC76dP38eJVYan/FysI7UgbWbJMqPDpN0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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