SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a9c3338449229fe754a3a1a3b2006d462aaf6aa784ff4728822fbbfb43aa11c' 
  AND token = 'PmX12icScvlVOv3FY0K8RuFiKDRJ4zECZ1WoxspTBN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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