SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3591b377619ece37d8f716a22c076910264b47a3112aeac8b2cbf7442eac0a66' 
  AND token = '3WET5eGnl4Ez0AERXnI7wuh7szS06EAyldbbZ27PhkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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