SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0aea2b3cbdad0f5b3fa651301fc98422f881c23f04a7d49b61276b7b9ff00531' 
  AND token = 'XLGsl+fzrAaUiQWnG6JVotvu8e38EEXy4pUlppcrbgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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