SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d4de6125a962a0c023767f08f0504a81d2b206fbddf02622ab059d822d34ed' 
  AND token = 'TeQNevM24wpOdXKT8xocQuCGtZCZhHupIO6KPT4ynGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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