SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad53dce59683f943bf37847b758a4b3565f3d6e4f9051852461f9e7ec2ec5e6' 
  AND token = '2ZoglkT/Reha6QhZ1ZBaJL8RZuYVLOdkINFNdwXTzdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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