SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da8a68af4b09e4421b9c2d02c9fe6cc383cedafc296b0fe55e4272be82e52edd' 
  AND token = 'OKPGGuvgakzBbjINRUTZ0QKJcS3nDEs9Mg8170vBeRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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