SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77279aab8f5e59e24681dbf2d12ca5207ef1489fa1d9d6c0d45c5d2154f5a6e9' 
  AND token = 'JPwKUQIzMq1Qe9G4FWw18C8NuGQL7fIwcmCxcGIFsEI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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