SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2a988d450a85c07b07657671dae248b3329be0915e1879434040bea47229f7d' 
  AND token = 'APYh+j8XbTuRxvblVezR4sgI5VYUqBb6V7ek8+ousVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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