SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85ad270a09dd9bb8c238b20090b09b29ffbbdba83c8765b407239aef06e53a4d' 
  AND token = 'rFvbbRFCHl5XAvfsDNkIjNVBksML9ZyDAXP6JylWRW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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