SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d6eecb0c82f36678f2edfd3cac6cf3531eea47dce61df9955aaf891f5338358' 
  AND token = 'xABAJcJM5TGlhboKQiQfQgBhtI0EzqSH/gfhEJaY1A8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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