SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '943d4839a6c9ebd016224d33900cd185dae6cd0922d28bdf820e35821c851edb' 
  AND token = 'XrwDeEnUS2Jm/nyRMGPqcgYAqXaJ+7uzL4es9Fffx98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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