SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639f99fbf84305f72c0ce0e7a632d6025548240bfa12898a35de3f3dc9f5ecff' 
  AND token = 'yn5ZogVIJG3cuW+HiYExOzUr1WQrGLhH2iYjIhw4uQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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