SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '934f13db1cc432de880e0817f7999e8b76643bfcda365bbbd71af58eb461ffd9' 
  AND token = 'wWLDBthWKEhhwuDjRi3P9ACHyNkgfJ6YWETTQDezk2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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