SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43f0383073ca7ddf40476f3612c381fd532e18ea80515eb266b6a18e6df718f8' 
  AND token = 'pDkoB8gGcmcy4lL40pnrRnKE8W1INpNS/BhFwk3OhJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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