SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81feedb9b86cf57f16116eaf1a023bc55722e5ba38c6d2e34ae8c835e0879efb' 
  AND token = 'fpyNpAz7R5jmOwnnMfuHINhrsgUOZEx6jt3z5gGnmpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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