SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24c815b9a68d85a117803fdf80ce8f0d98e2960cba450c9b96bcd3116a2436d4' 
  AND token = 'KxAmALMuD/XLlkkUyVsnuocI7YPbzg40r4fmjGy+/08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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