SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4c625a486d98da5b840e9e80cee9c883b561a677b905ff7ca37f4db9bf72370' 
  AND token = 'rR8CGYA7MqSso9ntjfYySudxljEvH7pcQ3N6VI/8N6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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