SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ad620dcaaa22917f1ab0c76b6977d96384a5c277b4ff7034f2b01d54874d92' 
  AND token = 'BJ1lwgGdGSqpUqjbJQXB9OYh6GVvRg74J7lYeWlISrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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