SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e7e9ad55e11b3b3696552a1a99694e919ba3cec03723e2e58a48e1963c0afc0' 
  AND token = 'mMrBnwdyVqtPK5/iBiHhIjOMUUzZMVRKgvRy4sFJKho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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