SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5b89612d37c4a212372c9810e6eb830a643cdeabbdd26fe5044ae1fa067fb15' 
  AND token = 'HK+Pwez9n3sJpIKSjuGaMoKBvk7+9eDcrTlbluyaMkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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