SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9fc6554bc54ee65b9a888052347734a187b09c6a9e97b6cc3db58ed96f8bb26' 
  AND token = 'KkgZS0TMtwrk+wMXEmz+ubJ9itUJ6nf04nOuo1bJubo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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