SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f6c5b7f681cc2cf83b150e4f39b051e013b60403e27263e0e1fb63e196a3f1a' 
  AND token = 'eqEhvfjzGr/1SSfrDkkUCF/PPq0rMc/eJyqu6mcaF7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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