SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b51b460ca28bf1e89afd9c213b348d7984bc2f38b82c420328fcb1893ae4afd' 
  AND token = 'RZ4ylLJJ+e5N8/LIZXqvvP/15NW7KuMQPtadW7Bfw8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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