SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92f614253e143ba63ffca54888b6b2621b3e21925ec60459ac3f62ea698af35f' 
  AND token = 'CD8GyxmyJfbvwoULX4FaDzuNNxiPIZRayzYJRKHIhqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}