SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778577a2614b7d0720ef34cb307c28726dbbf1bf0b6e35e5d16c9173976beb3f' 
  AND token = 'cBX4ouci71JvKsUbAyDJjEjG8mtttOVkIH7H1ZKFVp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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