SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f714dc19ffd7d6aebb5ede13b7b513e4224e783a5f1fcb8009cc0a2c2bbd8b9d' 
  AND token = 'M+a9SsAZlOYgKFSBqjHyzrjWXJqZMGdPJDeGmx+j0io=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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