SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db321787b6ba946dca6b03543c870eb3f41b22e3ecc3e47f465ff679cf76eeef' 
  AND token = 'lz8MRVnuWH22jvv5X7HsBVnJRvql+7K8CV+ntAoJZEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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