SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '63936d311405f1e190cc745f5706da2a814b60ed4a83affab2a33a3518d32f26' 
  AND token = 'lybVAexId2h5VzJOymX3OZfNF+jK2NoLQQavKOzTZBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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