SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bc5720036aa207a3a13247b580205783208ebbf9c4241bdcb4572dd81ef63e0' 
  AND token = 'Ly/gGQMTaJWImTC3ZGDHOg59OM2ONUZPDaRMqQZmjTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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