SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '713983de41cfd43983caddbc96cc1597cb5bb771293ecb2f9f556378a0c0f6c7' 
  AND token = 'q4XKX+kwj6YXUWPlIqROko5laEQY6wXvOemLQ4CtzjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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