SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d245d463e2ac563405f5957fe6e91a6d09ec8c81ed2a0caa24d0f51e1c06cd7' 
  AND token = 'wou0tCd4iYQIClcfCw42nQkjDdN9oumh3cwR2HueGP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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