SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c767b149f9ef342628b5717b0913b6a4616d9f2904c4b2c1bc8832e4585f97a2' 
  AND token = 'HAeyDjRwx5Ob8TTlgzARoKKcg7gqTjNNBZxyXOqPiRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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