SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e5f88c87c3e89f773e093f0dfffe04d68df6505c8a9d1d5069ee0710c97e1f7c' 
  AND token = 'UHkSTDwb3cmtd+I7f9k8Y8iFlauAonBxQOiIFZammHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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