SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a23800314e0f5888a8fc4b8a2df18c9a2fc584cd1cdd856a82ce5bdbeb8dae74' 
  AND token = '6DNpBHjwSbbFlUfG6J4clLrMfnfHnSPUuUEALlNSwQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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