SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71f15d301d7cceeea7925c33344516a454d8c2b8dacdc5162cf82a79def72951' 
  AND token = 'qdc1xA7oUUmFmTujrZSgq1m/EwJXnKt1NRU1H8NB7QU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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