SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b9fe1c919474837440dbb2e8f4f34e4e5bd60a738611fd8ef8e8e8ae031cf1' 
  AND token = 'UAeSaJdeeFayD47KsSFYSJAVKCs+J0a2BdeheABb6JU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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