SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dcef72f27a3f6a10464a7343e8c6bc9eaede1b510c3e418a1236399f1a427cf' 
  AND token = 'vMQfjEQscH9NixH1tBFYQUKeFc8h1x5n1VoIWzTjCvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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