SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15dc526187018e4f92efb202027411e5bf03d5c4659d74f9132dd8d1f1da5ee1' 
  AND token = 'tf9X7repusNR2f5DQzqR5sg0/oFfDFdQ7g6Lus7Y6jU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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