SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b5c46c05a420be074a363ce5f82f84d78bc9b0d425f775e708bcb56f5a908e1' 
  AND token = 'h7sJHMovWjlVMXvft8WtngHLQ8PaYnIcFYt0z5W+f6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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