SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5b3ba5d7fece02e53441cb4843df1bb838b54f8b5835c0335f8688ddf09c744a' 
  AND token = 'xollQWgtC+DnMvG2LwU7fYHZy9O87dvFhwLJevPBgVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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