SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc85475f40fb911937366c903780a8d5a9e70ad0429a3a5a169425a66a81be45' 
  AND token = 'i2mju18RhDQmOwDOd6NYDI/7SS0VuHgKBt6+RjXpOVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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