SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '921b16fa6fad372eee0670b884d685bdf952e2f0210289887a3824891d828314' 
  AND token = 'PUDLdHvbljjSVWmIVy21vKiIgvxVcCbCU6nR5sX8SuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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