SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2489f3b150534aa40e22d7bace87ad421eb42f0659b13635c83dc994b595ebc1' 
  AND token = 'fBn9hVK56JtbKTlYvdejo/3bl/XShQ3yS+rDyShk3/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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