SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '690163d0d2f405e48f949da47f754170dee88a40ddd0df19f7c58ef669b8f138' 
  AND token = 'nucxgH8FbQZDOiytZNjWWtz9VRcXDVuWs686ud/NAxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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