SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '343d2ef24a2f50f5a5ee4f0cbe2befd8c2ea979d001158d7dd102a78fef32361' 
  AND token = 'OJ83maYXs8zRQ2EhXJnaCH2+1C47t7PuCdshiMcDXT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}