SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '94684208f55f55e5bb06b1b3376eebc333107bc576273ac9d92c097fed920899' 
  AND token = 'NOIKPZ2PLaK3dLKwXfR8SaN2mgZtQVUP7q/Az9v9HEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}