SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54f79b0d8c502a7a69cd6e8024cf7b4367b280207006280425f7bca7c9b74c26' 
  AND token = 'SR/Ba5wO0/e9u1h4W5aS1xSv0wryD4Zza2C9S55ajH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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