SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959abd3294f45b105a8e0e55a7d8435946574eec77e4810a3c6b015d50c9dc0f' 
  AND token = 'owmPHPaz61Ak/QArCAsLtPWmQYRl+hs+vqQpTvqgLog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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