SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afb365e619cc31190f19742a9c9aec317746ff4f0563fbe6c6f324cd1086ed76' 
  AND token = 'x2CqKvmaTzkOoMdd901URAz+frs2qxyrDJQvxxOuGmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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