SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b748acd97389cc6f72468ba5648a0b88ba42ccccd611830cd81439468a7ea228' 
  AND token = 'u9a0zUabsmqev05TWKsDVydMAIl2NL5iZGJtv4oXsTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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