SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc9cf703ccedd7449738ef817adfe3ffd8d10c132e20738209c5d34c81a3368' 
  AND token = '1hvxYmtIrTq55P9ei67ylYvV8GYa9crfmm8sNHyxaXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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