SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdc16a8e6acc30ee7d2877ce124851a4630f0f5e2f027edd3983af4227d276b5' 
  AND token = '39sszxXe5AiqpYO8yersMa/N0kCuUlCkmlZGSQGa+Hg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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