SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '253668cd44e989b22fee50227215894d8a092296dab7e5b04834e104494698ab' 
  AND token = 'GqYJOKVJ/9O9M64KsENaVKwhkmwoVKIMoSCi3G+gZzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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